[Lots of things to kill? Sounds like right up his alley, honestly. When it's first going down, he doesn't even seem that concerned about it - kind of delighted for a chance to actually kill something and keep his hands busy. But it's quickly overwhelming, even if he maybe has thicker skin than most. (More injuries = more ability to fight, dem reaver abilities.)
Of course he's off to find Dorian as soon as he possibly can. Fightin' side by side!!1 and/or he knows this is quickly getting out of hand.
When he does spot him, though, he obviously sees the creatures he's fighting off -- but also sees the serpent, too. And it's clear Dorian doesn't. Which just means he's running faster.]