https://youtu.be/gGdGFtwCNBE

Coming out of my cage
And I've been doing just fine
Gotta gotta be down
Because I want it all
It started out with a kiss
How did it end up like this?
It was only a kiss, it was only a kiss

"Deep down, he's all fluff."

"Banner?" Tony gasped in feigned shock. "Banner's fluffy? The last thing I would ever call the Hulk is fluffy."

"Did you hear me say Hulk? I said Banner," you sighed, slapping him playfully on the arm. "Hulk is squishy."

All Tony could do was to shake his head in disbelief, laughing loudly enough that he could be heard even from the far side of the room standing opposite of the topic of your current discussion. "Honey, do me a favor and never tell me why you think that, okay? I'm conjuring up enough of my own scenarios to keep me entertained for weeks. It's not just anyone who gets to poke around at the Hulk to know his various textures and I don't want to know how it turned out to be you."

"You're dumb."

"You knew that."

"You're lucky that you're cute."

"And I knew that."

From the large bank of windows of the top floor of the tower, the lights of New York City reflected in his glasses as he stared off and into the distance, Bruce did his best to not listen, but even in a crowded room filled with voices and loud music your tone was the only one he could hear. He could hear the change of every individual note within your laugh, and the shift in your volume as the laughter calmed and Tony had inched ever closer to you to leave a trail of kisses along your neck. He swore that he could hear your heartbeat begin to race and your breaths turn shallow before he could suddenly hear no more. When he finally willed himself to turn around and look for you, he berated himself in silence for being fool enough to think that his intuition was wrong.

It was never wrong.

The two of you were gone, and he had no desire to give a moment of thought as to where you and Tony went even though he knew well enough. He wasn't stupid, no matter how true he felt it to be.

But that's all that his genius mind could do; torture him with imagination and rumination and fill his senses with a coldness that only you could warm. He knew that it would never happen for him, and that he had nothing real that he could offer you for a life together, but dammit if he didn't want to try anyway.

He would never tell you any of this, instead doing his best to make you believe that he was happy for you and happy that you were the one to make his friend smile like no one else had. Bruce had spent his share of late nights in the lab, unable to sleep when his mind wouldn't stop. He had watched Tony stumble in at all hours during the dark, wordlessly working on some idea born within a dream until it had reached its limit, only to turn and leave just as quickly without so much as acknowledging that Bruce was there. The first few times it had happened it shocked him a bit, but he was used to it now. He had become so used to Tony's wanderings that he missed them now that they weren't happening anymore.

They weren't happening because he knew that Tony felt safe with you and that you were next to him to give him no reason to walk away for even the greatest ideas he ever had.

Now I'm falling asleep
And she's calling a cab
While he's having a smoke
And she's taking a drag
Now they're going to bed
And my stomach is sick
And it's all in my head
But she's touching his chest now
He takes off her dress now
Let me go

"Hey, you okay?"

"Hmm?" Bruce mumbled, shaking his head at the new voice next to him and gentle hand on his arm. "Oh, o-oh yeah, I'm...I'm good, Nat, thanks."

Natasha studied him as only she could, taking in the smallest hints of a clue as she chewed the inside of her lower lip in deep concentration. Next to you, she likely knew him the most, at least about Bruce in a way that was beyond teammates like the rest of them did. They had their short-lived time together a few years ago but that's nothing more than history now, and they came out of it all as better friends and sharing an unspoken protectiveness over each other. When she could feel his demeanor shift and watched his posture all but drop into what she could only call evisceration, she knew she had to move. "Sure, Bruce, you look fantastic. What's going on?"

"Nothing, really."

"You lie worse than Steve."

"I thought he'd gotten better?"

"If that's the case," she smirked, "then you're that much worse. I think that instead you should give me a shot at maybe being able to handle the truth." When he turned back and away from her again with a woeful shake of his head, she didn't allow him to hide this time. A few quick steps put her directly in front of him, forcing him to look at her and actually listen. "How long before you trust me?"

"Nat-"

"Bruce, whatever you say to me will stay with me, I promise," she whispered gently. "Whatever it is that's making you look this sad shouldn't be kept to yourself to hurt you the way it is. Maybe just saying it out loud will help you finally work past it."

Bruce's expression shifted, shocked but then quickly recovered to hide it even though he knew full well that there was no way that she didn't catch it. She was too smart, too skilled, and he knew that she knew but was simply forcing him to admit it. "W-work past what? I don't...I d-don't know what you're talking about, Natasha. Excuse me," he tried to turn away, "I think I'll just head to my room-"

"No," she answered, taking his arm into her grip, "I think you'll stay and let me help you. Or I can follow you if you want, but that might get the gossip queens all riled up. Clint and Sam are still here and you know they run with even the dumbest ideas. But let's entertain this, what if they actually get it right this time? Are you ready for that to get out?"

"I don't know what you mean?"

"Do you really want (Y/N) to know that you love her when you haven't even had a chance to tell her for yourself?"

And I just can't look, it's killing me
And taking control

Jealousy, turning saints into the sea
Swimming through sick lullabies
Choking on your alibis
But it's just the price I pay
Destiny is calling me
Open up my eager eyes
'Cause I'm Mr. Brightside

After spilling his guts out for the better part of the last two hours, Bruce finally took his leave of Natasha and the party that he had no interest in, making his way to his room on exhausted legs. They were the same legs that could turn into those of a beast, the strongest Avenger, and the most feared Avenger by anyone who didn't really know him.

You really knew him.

You were right, Banner might be all fluff, but the Hulk was squishy. As much of a rage monster as he was, it was never the case around you. Both of his personas were taken by you, neither of them able to deny your power that eclipsed any power that they carried on their own.

The doctor stood immobile in the elevator, counting the floors as they passed by, taking an eternity to bring him down to his only means of escape and the solitude of his room that he needed so desperately. His worst nightmare now would be that he'd see you and you'd know. He was too open now after his talk with Natasha; his soul was open, bleeding, and raw, and he knew that he sucked at hiding it. One look and you'd know everything without a single syllable spoken. He couldn't risk that. He couldn't do that to you. Your laughter with Tony was genuine and wonderful, and he relied on hearing it even if it had to be brought out by someone other than himself.

When the doors opened and the sound of that laughter hit him like a wave of nausea, he wanted to take that sentiment back. He never wanted to hear it again, but now it seemed to be coming from every direction and it was choking the life from his chest. The doors began to close again before he took a single step to leave the lift, and when your voice became clearer through his haze he pushed his hand forward and held them open for you when his arm moved against his own will to stop it.

"I'll be right back, ya big baby!" you called back towards Tony's room as you crossed the threshold into the elevator. "I'll bring something for you, stop whining! Oh! Oh, Bruce, um...hey...I didn't see you there, sorry. I can wait for the next one-"

"No," he hurried to say, taking your hand in a near-panic as if it were natural to do so. When he realized his error he released you, turning just slightly to hide his face. "I'm just headed to my room, nothing urgent. Where to?"

"Kitchen. We ate at the party but I feel like I should find something with a little more substance. I don't think I'll last until morning on bite size food."

"Hmm, probably not," he mumbled softly.

"Hey, are you okay?" You asked, seeing his posture shrink and practically sulk away from you like you had never seen from him before. His demeanor put you on alert and you studied even the smallest nuance in his movements to find a hint that you knew he'd never offer on his own.

"Sure," he nodded faintly, "just tired. It's been a long day."

"Do you want me to bring something back for you? I don't mind if you need something to help you sleep. You don't look like it would be the best night for one of your random lab sessions if we can ward that off."

"No, I'm fine," he continued to deflect, and it confused you. He was acting strange and you wanted to get to why. "It might be a good night for the lab, actually. I'm sure that Tony won't have an urge to show up tonight from the sound of it."

"What?"

Bruce's eyes widened at his brazen error, and the simple fact that he had just sounded like a complete and utter asshole to you. "I mean...um...if you're spending the night...I mean, you were laughing pretty loudly..." he stopped, a groan under his breath as he tried and failed to wipe the frustration from his expression with a quick swipe of his hand. "Nevermind, (Y/N). I don't know what I'm talking about. Have a nice night. I'll stay out of your way."

The door opened again and he didn't seem to care if it was the right floor or not, simply rushing to get away from you. "Bruce, stop. What's going on with you? Something's wrong and you do a really terrible job at hiding it. You won't even look at me." Much to your relief, he stopped at the edge of the door, but he still faced away. "Banner, turn around."

"I need to go, (Y/N). I can't...I can't do this right now."

"Do what?"

"Be next to you. It's not personal, I promise."

"It kind of feels personal."

Once he glanced back over his shoulder to see you, finally, his mouth opened for just a second as if you might have broken his resolve and he would let you in on this secret that you wanted to hear so desperately now. Bruce felt the nerves building and his heart begin to race into that unsafe rate that brought his alter ego, and his adrenaline surged not from anger but from embarrassment at what you were able to see in him; what you could see through him and it made him almost welcome the Hulk just so that he could hide within the mask.

You could see a hint of green just at the edge of his hairline and the most subtle change in his eyes, leaving you to take a step back as if you had done something terribly wrong. Maybe this wasn't the time to push, but you wouldn't let this go. Hulk didn't scare you at all, but you were hurting Bruce in a way that you didn't understand and you couldn't do this to either of them. "Bruce, I'll go. I'm sorry...for whatever it is that I've done..." you said slowly, backing away and into the lift again. "I don't want to hurt you, so I'll just go, okay? I'm...I'm sorry..."

Bruce looked down at his hands in terror and shoved them into his pockets, hurrying away as he whispered back, thinking you wouldn't hear, "you could never hurt me, (Y/N)."

As the lift doors closed and created the barrier between you, his words carried just enough sound to reach you before you could answer him. They carried just enough for you to understand the meaning behind the pain in his tone without the time to reply. He knew that you would see it now, and he had ruined it. Even though his words reached you, they wouldn't be fast enough for you to catch him before he could run.

When the elevator doors finally opened again and you considered returning to him, the next sound from Bruce stopped you in your tracks. The low rumble started with the familiar tone of the gentle man who was one of your closest friends, quickly deepening and shaking the floor beneath your feet. As the Hulk transformed and ran for freedom, you weren't startled at all as Tony appeared behind you, gently taking your arms to hold you to him as if he thought you might give chase.

"He'll come back," he whispered softly. "He just needs a little time, is all."

"You knew, didn't you?"

"Yes."

"Why didn't you tell me?" you asked as your voice cracked under the strain of realization. "I could've stopped him."

"Because he didn't want you to stop him, honey. He doesn't want to put you in that position, to feel like he's a burden or to hurt your friendship with this. He'll come back. He loves you too much to leave for good."

"And you're okay with that?"

Tony hesitated for the briefest of seconds, what would have been barely noticeable to anyone other than you. There was no lie in his answer, he just didn't enjoy it being the one he was about to give. It was a vulnerability that he was gifting to his friend, a promise to the doctor that he had made when he found out about how he felt; a promise to understand and never let it come between them, and never between you and Bruce.

"Yes."

I'm coming out of my cage
And I've been doing just fine
Gotta gotta be down
Because I want it all
It started out with a kiss
How did it end up like this?
(It was only a kiss), it was only a kiss