He’s reminded, in that moment, of how different their worlds are. Malia instantly assumes that the spirit was killed, maybe as she would have dealt with an enemy in the wild. It should weird him out maybe, but it mostly endears him to her.

“Well, you can’t kill a ghost. They’re already dead. You can exorcise it…or trap it, which is what we did.”

Not before it possessed him and took his body for a short joyride, but he doesn’t mention that.