The idea of Goyle even knowing how to swear an Unbreakable made Alfie's eyes go wide in a sort of terror that hadn't been there before. That was advanced magic, and fucking serious, and he got a feeling for just how dangerous this situation really would be.
"What would I have to do?" he asked, defensively, but then he thought about Julien and what would happen if he didn't, and he added a hasty, "I'm in."