Didn't have another choice, for one thing, I'd reckon.

[He pulls the leg of James' trousers up, looking at his ankle and holding his wand up in the hopes of something coming to him.]

Don't worry though, mate. Whatever this is, it's likely something to do with the island. Should be over soon. By the way, did I tell you? Remus ended up becoming a teacher, at Hogwarts.