This is such a great sequence of him reading the booklet with idle curiosity, discovering the miracles aren't working, then going "Fuck, I'd better learn how to do this trick!"
Still no idea why they didn't just run away though. Maybe they just fear an awkward social situation even more than death.
..... actually, that would explain a lot about their relationship.
They're British, they absolutely fear an awkward social situation more than death.