He did stumble back when she pushed him aside but caught himself and didn't really blame her for it. Finn really wanted to crowd over her and ask if she was all right, but that would be unwelcome.

So he stayed back and crouched down lower to the ground so he didn't tower over her either. His Chemist job was already active if she needed something, but otherwise, Finn watched for anyone coming towards them.

He was prepared to wait it out. Or leave if she started demanding it of him.