Halo 2 Anniversary - walkthrough part16

You have to hide under glass floor at the near of the end of mission otherwise the doors won't open...

Copilot dialog :
in halo 2 aniversary there is mission heretic. Last checkpoint is deal with tatarus, i killed first wave - monkeys and nothing happend, there should open gate and second wave should come but did not. What should i do?
It sounds like you've hit a known bug in Halo 2: Anniversary during the "Heretic" mission (specifically the Oracle level). After defeating the first wave of Brutes (aka "monkeys"), the gate should open and the next wave should spawn—but sometimes it doesn't due to a scripting glitch.