I could work with that, sure. Billy's getting adventurous enough with his magic that while he respects Loki's knowledge, he figures their abilities are so different that Loki sometimes underestimates him. And he'd think that since he did it once already, trying it again on a smaller scale wouldn't be too difficult.

He'd also feel proud enough of his success that Loki bitching at him for it would irritate him a fair bit :|a