Well, the domino effect seems to sort of happen anyway, but at least they don't all fall backwards. Dream or not, landing backwards on the stairs and having both Peter and Daniel (especially Daniel) fall on top of him would've been pretty damn painful, if not potentially deadly.

Instead though, his arm too gets yanked up and forward, making him trip as well, though at least he has one free hand to break his fall a little and make is slightly less painful when his shins and knees hit roughly against the stone steps. Which, still, ow.