You had gotten yourself a cup of coffee and were watching Gina insert the specimen into the Anti-mass Spectromiter. Then everything went to hell. You overheard one of the scientists calling it a "Resonance Cascade" you remember seeing some notes on Gina's desk on the resonance of objects. Then, in a flash of green light Gina appeared next to you.

Gina: I don't wanna be a schizophrenic! Oh. Yeah, all right! I'm not in crazy land anymore!

A green beam of death blasted through the window in the control room.

(Y/N): I think that's our cue to leave.

Gina: Yes it definitely is.

The two of you ran as fast as you could to an elevator.

Gina: Hey where's the elevator?

She pressed the button, causing the elevator to fall to the bottom and killing the three people inside. You looked at each other for a second before deciding to climb up the maintenance ladder, hearing gunshots at the top.

Gina: I hear gunshots. Someone's going postal!

You reached the top seeing one of the other guards shooting a... thing.

Allen: (Y/N)? Gina! Man am I glad to see you two. What the hell are these things, and why are they wearing science team uniforms?

Gina: I couldn't give you the slightest explanation.

(Y/N): We're not getting anywhere standing around with our heads up our asses. Let's get moving.

Allen: Yes sir!

Gina: Better than standing here and dying.

The three of you were able to get to the front desk.

Allen: You two try to get to the surface I'll try to contact someone from here.

You and Gina nodded both thinking to yourselves "he's gonna die here," before walking through the door to the inbound catwalk.

(Y/N): The tram's gone.

Gina: Wait how'd the guard die? (to scientist on catwalk) You kill him? I want answers!

The catwalk collapsed underneath him leaving you and Gina with one option for escape, an air vent going into the programming room.

(Y/N): (yelling over music) I can see what you were talking about.

Gina: I don't know what killed the people in here. If the aliens got them, or they raved themselves to death.

You both crawled through another vent to the door to sector B. Outside the door Gina found a gun to use.

Gina: Now you don't have to take point all the time. What do we have here? Semi-automatic, some sort of Glock, good thing I've seen Die Hard 50 times.

Hearing that made you feel just a little bit uneasy.

(Y/N): Somehow, that doesn't give me the most confidence.

Gina: Whatever.

With that the two of you continued through to find the administration offices and, by extension, a way out of Black Mesa.