Steph would have had a similar pose if she didn't have the grenade and batarangs at hand but she did so she returned a look that conveyed exactly how she felt about him. In short, she didn't trust him and she still wasn't sure what was going on but no one was getting robbed tonight if she could help it.
She had to admit that the web-shooting was cool but no way was she going to say it out loud. Instead she threw the batarangs at the remaining thief who was just about to get up and run and smiled when the batarangs knocked him squarely in the jaw. That had to hurt. "Hey don't go hating on Scrooge." she added and pointed at Spidey.