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

Did you know you can donate one or all of your vital organs to the Aperture Science Self Esteem Fund for Girls? It's true!

Please be advised that a noticeable taste of blood is not part of any test protocol but is an unintended side effect of the Aperture Science Material Emancipation Grid, which may, in semi-rare cases, emancipate dental fillings, crowns, tooth enamel, and teeth.

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.

This is your fault. It didn't have to be like this. I'm not kidding, now! Turn back, or I will kill you! I'm going to kill you, and all the cake is gone! You don't even care, do you? This is your last chance!