There's little that happens in Gotham without Bruce knowing. He is obsessive by nature and in the wake of the death of superman this hasn't gotten any better. There seems to be more to fight for now, more to lose. When he isn't working with Diana to try to find the other metahumans like her he's on the streets patrolling. No matter what else happens, Gotham is always a priority. That hasn't changed. So when he finds a kid using what looks to be a batarang against the criminals he had been tracking it puts him on alarm. He doesn't want people copying him and getting hurt.

(There's a damaged Robin suit in the batcave to remind him why other people can't be like him)

His voice is gruff and distorted as he speaks.

"You're lucky all that happened was that wall."