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

Time out for a second. That wasn't supposed to happen. Do you see that thing that fell out of me? What is that? It's not the surprise. I've never seen it before! Never mind, it's a mystery I'll solve later... by myself, because you'll be dead.

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!

As part of a required Enrichment Center protocol, the previous statement that we would not monitor the test area was a complete fabrication. We will stop enhancing the truth in three... two... zzzt

You are not a good person. You know that, right? Good people don't get up here.