There was even going to be a party for you. A big party that all your friends were invited to. I invited your best friend, the Companion Cube. Of course, he couldn't come because you murdered him. All your other friends couldn't come, either, because you don't have any other friends because of how unlikable you are. It says so right here in your personnel file: "Unlikable. Liked by no one. A bitter, unlikable loner, whose passing shall not be mourned. Shall NOT be mourned." That's exactly what it says. Very formal. Very official. It also says you were adopted, so that's funny, too.

Momentum, a function of mass and velocity, is conserved between portals. In layman's terms, speedy thing goes in, speedy thing comes out.

Remember, the Aperture Science Bring Your Daughter to Work Day is the perfect time to have her tested.

Good news. I figured what that thing you just incinerated did. It was a morality core they installed after I flooded the Enrichment Center with a deadly neurotoxin, to make me stop flooding the Enrichment Center with a deadly neurotoxin. So get comfortable while I warm up the neurotoxin emitters.

Look: we're both stuck in this place. I'll use lasers to inscribe a line down the center of the facility, and one half will be where you live, and I'll live in the other half. We won't have to try to kill each other or even talk if we don't feel like it.