Early on, Jack made a run for Izzy when he saw the first man bearing down on her. Until she dispatched him in about six seconds, took his pipe, and knocked him soundly unconscious. It was very efficient. It was ruthless. It was one of the hottest things he's ever seen her do. His momentary surprise lets someone get a good shot in on his knee, and that's not ideal. While he deals with it, she moves on, but he's no longer worried about her.

They cross paths properly a little while later. Izzy stops someone from attacking Jack from behind, and when he turns to thank her, he throws the pipe in his band back over her shoulder, hitting a man square in the forehead and lunging for it when it arcs back through the air. "You look good out there." Yes, he's flirting a little. He's also being vigilant and scoping out his next move. He can do both.