Originally Posted by
Hyoi
I feel like y'all are all dancing around the most likely explanation of the trap's mechanics: it's not a trap at all, just an always-on portal that links the door to its associated dungeon crawl, which is located somewhere else. Disarming the trap temporarily turns off the portal, so the different-colored floor behind it is just what is actually there behind the portal. Team evil hasn't noticed the trap because simply walking in doesn't trigger any detectable change. The OOTS might have made the same mistake if Haley hadn't stopped Roy before he could step over the trap. After the 20 seconds are up, the portal will turn back on, so anyone following the OOTS will end up on the standard path.
Bonus points if the runes don't actually create the portal, just provide a means to turn it off, so the dungeon fails safe if someone just destroys the runes. That would mean that without a rogue team evil has no way to bypass the trap even if they know it is there.