Yeah, he is hanging around after her, but I still don't see any chemistry there. His flirting seems very perfunctory to me (it being expected of one to flirt with the pretty coworker), and I've never seen her return it. Honestly, I think Sam and Martin have the least chemistry of any type- romantic, friendly, whatever- of any two characters on the show. He never relaxes around her, and the chip on her shoulder blocks him out. I can count on one hand the number of non-antagonistic conversations that they've had. They just seem like a recipe for an unhappy relationship, and neither one of them, damaged as they are, needs that. Aside from which, it strikes me as odd that Sam would go from an unhappy, dangerous affair with her boss to a potentially unhappy, dangerous relationship with a coworker. She seems more careful than that.

Naturally, all of this is my opinion, and disagreement makes life interesting. But I just really don't see any spark there.