Gordon Freeman, in the flesh - or, rather, in the hazard suit. I took the liberty of relieving you of your weapons. Most of them were government property. As for the suit, I think you've earned it. The borderworld, Xen, is in our control, for the time being... thanks to you. Quite a nasty piece of work you managed over there; I am impressed. That's why I'm here, Mr. Freeman. I have recommended your services to my... employers, and they have authorized me to offer you a job. They agree with me that you have limitless potential. You've proved yourself a decisive man so I don't expect you'll have any trouble deciding what to do. If you're interested, just step into the portal and I will take that as a yes. Otherwise, well, I can offer you a battle you have no chance of winning... rather an anticlimax after what you've just survived. Time to choose...

Eli Vance: "Why didn't they listen? We tried to warn them."
Scientist 2: "I never thought I'd see a resonance cascade, let alone create one."
Eli Vance: "Gordon, you're alive! Thank God for that hazard suit. I'm afraid to move him and all our phones are out. Please get to the surface as soon as you can and let someone know we're stranded down here. You'll need me to access the retinal scanners. I'm sure the rest of the science team will gladly help you."

Come in, Cooper! Do you copy? Forget about Freeman, we're abandoning the base. If you have any last bomb targets, mark them on the tactical map. Otherwise, get the hell out of there! Repeat, we are pulling out and commencing airstrikes, give us targets or get below!

Gordon Freeman - it is you, isn't it? The Science Team has been tracking your progress with the Black Mesa security system. Unfortunately, so has the military. That suit of yours is full of tracking devices. Still, it's better than going naked in this place. It's cold in there, and you'll have to hurry. It could sap your suit power in a matter of moments! If you're bent on reaching the Lambda Complex, then you'll want to keep to the older, industrial areas where the security system is full of holes. It's worked for me, so far.

Well, so much for the government, their idea of containment is to kill everyone associated with the project! Judging by your hazard suit I'd say you were part of what went wrong, isn't that right? Now look, if anyone can end this catastrophe it's the science team in the Lambda Complex at the opposite end of the base. With the transit system out I couldn't tell you how to get there, but there's an old decommissioned rail system somewhere through here, beyond the silo complex. If you can make it through the rocket test labs, you might be able to worm your way through the old tunnels to track down whatever's left of the Lambda team. You can trust them. You can trust all of us. Good luck.