[Drusilla is EXACTLY why he's out here. Sabriel warned him, Buffy told him what to look for, and Ginia's injury perturbed him just enough to spur action]

Mana. Energy. Alright, I understand.

[Luke removes his heavy robe and tosses it to the stranger.]

Cover up, if that'll help contain the lights. I'm fairly certain it may attract any manner of nasty creatures.