Second Sight Easter Egg - Hyperchat

At the third level, where John is going down in the elevator and accidentally kills a guard with the Psi-attack, go to the computer that unlocks the door. Then go to the "desktop" and at the bottom there will be a "HyperChat" application. Open it, and you'll see the chat of the guard with his girl.

The interesting thing is that the guard typed that the elevator is going down and he didn't want anybody to see him chatting. And his girl is worried why he didn't type back.