At first glance, Miguel's co-worker seemed harmless enough. So, the fact that he smiled back seemed equally harmless. The woman with the blatantly red hair was simply being friendly, and should be treated with equal friendliness.
It was the warning glance from Miguel that raised some warning flags. As well as the predatory gleam Jack caught a glimpse of. Female attention he was used to, mostly brushed off if he noticed it as all. This was one of those occasions that he had to resist the urge to put up his hands and back away slowly. As he would treat a situation with two angry females, or an angry dog.
As much as he tried to hide his reaction, when Marla moved a step further with her pen, that time his eyes did widen. With a clear, 'Ayudame!' in his expression. Save me Miguel!
The moment she said Miguel could go, Jack was out of that room as fast as humanly possible. "/What does she possibly think my number will help her with? We're on a ship...I don't even know my number./"