[ sitting around, doing nothing isn't mamoru's style, either. he may not have his powers right now, but he's still a med student whose had first aid training and has copious amounts of medical knowledge under his belt. he's been running around, putting those skills to use in helping those who've been injured or are suffering in some way from the frigid temperatures.
it's something to keep his mind off the fact that usagi appears to have vanished, at least.
or it did, until stiles had to go and say something like that. ]
Maybe it does, but that's kind of hard to do when there's no true love around to kiss.