John watches as Sherlock triumphantly types the passcode that Irene has just revealed-on the fake phone-into the real phone. He sees his disbelief as it fails. John is as surprised as Sherlock.

"I told you that camera phone was my life," Irene says. "I know when it's in my hand."

"Oh, you're rather good," Sherlock says.

Irene smiles. "You're not so bad."

They stare at each other in mutual admiration. John feels a deeply unpleasant stab of... something... in his gut as he looks on. He wants to interrupt, to say things to each of them.

Firstly, to Sherlock: This is the same woman who made you think she was dead. Who made you more miserable than I have ever seen. She doesn't deserve you looking at her like that. She's just going to hurt you again.

Secondly, to Irene: Hurt him again and I'll kill you. Simultaneously, he wants to ask her, Why are you flirting with him if you think we're a couple? What makes you think I share?

Oh.

Jealousy. That sensation would be jealousy, apparently.

Jealousy? Really? Over Sherlock? He hasn't the first clue what to do with that epiphany. So he makes a joke.

"Hamish." This elicits general confusion. "John Hamish Watson-just if you were looking for baby names." It's not a great joke. He's not at his best, right at this moment. In fact, he's a bit shaky.

He hopes he isn't showing external signs of his emotion-he can feel his thudding pulse, is sure Sherlock could detect more tells-but then, Sherlock is too distracted to notice, isn't he? A thought which doesn't help matters at all.

And now Irene has Sherlock's attention to an even greater extent, as she presents him with a mystery. She kisses his cheek, and John feels his insides twist once more as Sherlock rushes to impress her in response.

Right. Jealousy. John wants... he wants Sherlock? He certainly wants Sherlock to look at him like that, to try to impress him-but not her. Does he want Sherlock in other ways? The thought is foreign; he doesn't know how to evaluate it. He doesn't usually like men. On the other hand, she doesn't usually like men, either, as she pointed out, yet she seems to enjoy kissing him, flirting with him. And Sherlock... what does Sherlock like? Does Sherlock like men? Is there any possibility that, if John did want something physical, his desire would not be disastrously unrequited?

He wants to ask Sherlock this, before this absurd flirtation goes any further and he loses Sherlock in a game he hadn't known he was playing.

"I would have you right here on this desk until you begged for mercy twice." Irene purrs in response to Sherlock's deductions.

John looks again at the way Sherlock stares at her. And he kept her camera phone with him, didn't he? John doesn't know if Sherlock likes men, but he likes this woman, and seems to want her in a way that he's never given signs of wanting anyone else. And... she hurt him, yes, but she was in mortal danger-he very grudgingly admits it. She's here now, despite the danger, and she wants Sherlock. Clearly.

It would be selfish of John to stand in the way of that mutual desire, wouldn't it? After all, it's not as if Sherlock has ever looked at John like that. Maybe if he tried flirting? No. Stop. Don't think about whether that was ever an option.

John settles for giving Sherlock a chance to be happy with someone. But he also knows that if Irene hurts him again, he will show no mercy.