The beginning of the 6th level.
A dead man on the floor (mental echo), another one stuck in a ladder ("2"). In the past, there's another man with a submachine gun on the metal platform ("3"), telling the first one not to climb the ladder or he'll shoot, which he evenutally does.
I guess the point is not to let the "2." dude die. I can pick a handle or what is it and lower my own ladder ("1.") in the past. Then I can climb to the same level as the "3." guy. Now what? Seems like I should switch some buttom or something so when the "3." guy shoots the pipe, there would be no steam that would kill the second one. Is that correct? Cuz I can't seem to make it in time, the echo always fails and I've tried like 20 times already. Any insight? Many thanks.