She was telling him that she doesn't date colleagues and that is her policy.

Him: Really? Luckily I didn't chase you that time.
Her: Yeah.
Him: So?
Her: So what?
Him: But we are not colleagues anymore now.
Her: Hahahaha so?
Him: So I chase you.
Her: Cannot!
Him: Why? Yo!
Her: Hahahaha you are fun and I don't want to lose you as a friend.
Him: I won't accept this reason.
Her: Wow, I didn't know you can actually won't accept a reason for such thing.
Him: Yeah, let me think. It's like programming. IF-THEN-ELSE. Haha.
Her: So what is the "if" and the "then" and the "else"?
Him: IF you are fun and I don't want to lose you as a friend, THEN I won't accept those kind of answer, ELSE I will chase you.

LOL! What the hell? That's the kind of answer you get from a programmer.