Other possible refugia (albeit temporary perhaps) include, as previously mentioned, prolificity, low predator density, or even they just tasted bad.
I see we can add "refugium" to the list of words you have private definitions of.
Re: bipedal climbing, given a favourable substrate, reasonably fit people can run up inclines of 45deg without much trouble. I wouldn't bet that *Saurophaganx* or *Giganotosaurus* could repeat the performance, but I bipedalism in itself doesn't prevent it.
-- Andreas Johansson
Why can't you be a non-conformist just like everybody else?