It probably seemed to poor Jack as if he were being watched. Shadowcrest could be considered the ultimate haunted house for how it behaved and could definitely give the impression of someone looking over your shoulder. Zee tried to hurry...so she might have cheated a little with the food.
She came back in with a plate of grilled cheese sandwiches including a bottle of ketchup. If he mocked her for that she was going to punch him.
"Kind of simple fare since I wasn't expecting company."