Perhaps it was the moment when she turned tail and ran, triggering some sort of predator instinct in him to give chase. Maybe it was the heat scent wrapping through his mind, switching off what good sense he might have had. Maybe it was the rage and fear that still pounded through him. Maybe his face just really, really hurt.
Whatever excuse Loki might have made in his own mind to justify his actions, instead of choosing to let the girl go, and probably get lost and die anyway in the crypts, he followed her. His much longer legs ate up more ground than hers, and when he leaped forward next it was with the intention of setting his teeth into the scruff of her neck, to stop her from her headlong flight. A certain savageness burned through him at the action, the inevitability.
