Other mistake: Once outside in the rain, Gambit throws 4 explosive cards at Nightwing. The first three hit walls and truck trailers but have absolutely no effect on the environment, where the fourth one causes lots of rubble to fly as Nightwing rolls out of the way.
Continuity mistake: As the fight part starts, Gambit walks into the room and sets a small suitcase on the table with some tools. When Nightwing later flips over this same table, the suitcase and tools have vanished. And then they appear again after Gambit blows Nightwing through the wall as he grabs the suitcase off the table.