Doom 64's MAP30 secrets

[ZeroTheEro]

Anyone have any idea how to open the room containing the plasma gun (where multiple health bonuses are lining right outside, and there's one you can't pick up unless the ledge is lowered)? There's also two lifts containing two ammo box pickup that for the life of me I can't find a way to lower them. I managed to do open the former secret once by accident but I can't find a way to replicate it.

 

plasma gun room

 

the two lifts with ammo boxes

[Nevander]

Very commonly missed. At the center of the atrium, go up the middle stairs and into either side rooms. Walk through both windows here overlooking the stairs on both sides.

[ZeroTheEro]

Good lord, there it is.

 

Thank you, Nev. The untagged secrets are driving me crazy trying to figure out how to open them.