She's not used to people sneaking up on her (not that Stiles really did). Malia's just so focused on trying to figure out how to get inside that she doesn't hear him approach, and he's downwind, so she doesn't smell him, either. Her look of surprise when she turns to see him is completely genuine.

"No. I'm just... hungry. And I can't go dumpster diving again because it's too risky, I was here earlier this morning." Malia grimaces, turning her glare back to the door.

"But I don't have any money."