Not sure how I could fix this. I made the enemies teleport when you shoot the former human to demonstrate that the next part was going to be a rush to the lift. I have it so that the walls are impassable and can be seen through by the enemies (so they think they can path toward you) but then they teleport before they can. If it were a closet that opened after hitting the linedef in the HK room, you would lose that demonstration in the beginning.
I originally had the lift raise faster than its current state, but then it was frustrating to speedrun as you would exit the HK room after pressing the switch and the lift would be raising. I added the door to make the player shoot while not in line of sight of the enemies but that doesn’t work too well. I think you’re right in that I should add monster closets (and maybe add a few extra imps/shotgunners) and make the pinkies chill there at first. Would remove a bit of the luck involved with running it. Not sure how to avoid the player being able to cheese that section by letting the enemies just go down the lift, any thoughts?