Board Thread:False Info and Speculative Discussion/@comment-24732895-20150630102249/@comment-4091815-20150705224205

You're expectations of Theo's actions/feelings are getting in the way of what we actually saw on screen.

He did get out in front of them and up a tree in order to jump down and surprise them just seconds after his stop on the bridge. So, at some point, he became aware of their presence. Given his werewolf abilities - that awareness came sooner rather than later.