It's not impossible? But even if the stuff didn't knock him out right away, there was enough that it should've been really disorienting. If he did pull himself together enough to decide the first person he saw did something to him, and then decide to try fighting them, they wouldn't have been very good hits.

Looking at the footprints, I think it seems like he was just stumbling around instead of really...doing anything. And there's only one set...