In a real fight, Enjolras would have kicked the cane away. (In a real fight, the amount of damage both of them would have taken from some of those blows would have shortened the fight significantly -- although the winner would very likely have been facing other people too, during and after, in a general mêlée.) Here and now, he's scooped Bahorel's cane up instead, in order to pass it back to him.

"In the next match, he'd likely have been winner instead."

Percy doubtless knows this, Bahorel certainly does, but it's worth saying all the same.

Anyway. He steps back to watch, out of the way.