Area and state regulations do not allow the Companion Cube to remain here, alone and companionless.

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

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

The Enrichment Center is required to remind you that the Weighted Companion Cube cannot talk. In the event that it does talk The Enrichment Centre asks you to ignore its advice.

That thing you burned up isn't important to me; it's the fluid catalytic cracking unit. It makes shoes for orphans... nice job breaking it, hero.