When you've completed the game, you can start a new playthrough with developer commentary enabled. If you haven't beaten the game, be warned that some commentary may spoil puzzle solutions.

In this chamber, you'll find a commentary node from:

Next to the door you're forced to wait behind for a few seconds at the beginning of the chamber.

[Jason Brashill] In early versions of this map, playtesters would charge down the stairs without noticing what was creating the portals. We introduced a mandatory pause in the action - what we call a gate - to help ensure that players stop and notice the portal gun making a blue portal. A particle effect and a loud noise help draw their attention.