Peter had stopped moving. James was the leader of sorts, for their little friendship, the group that they had created and dubbed the Marauders.
In a sense, whatever James did was followed to a T.
Peter had never really stopped to question anything, to ask whether it was right or wrong, if he should be helping or going along with it all....now though, he found himself doing just that.
James had stunned Sirius!
He supposed he had never seen anything more strange, and could not bring himself to answer Lily's own confusion, instead he forced himself to move forward, just as Remus appeared, helping James to pull the other teen out of sight.