So I have a theory so hear me out.
You know how in the first episode we saw some foreshadowing in the first scene when Issa was on the phone saying she don't fuck with Molly anymore? We all were assuming Molly is the problem based on her comment about Issa working with Lawrence's current GF. Well, what if they fall out because it is really Issa that is the problem and Molly is right on how Issa's life is messy.
We now see Lawrence's reaction to the situation. He doesn't like it at all. It is one thing to try to be cordial to a business partner that is your ex's GF, but it is a whole 'nother level when you become "friends" with her and laugh at your ex's quirks. Also, Issa's has no discerning interest in TSA dude and he is merely dick-on-call and that turned into an "Oh shit" moment. I think Molly was starting to think that maybe Issa was on to something about her attitude, but when she got that call and dude admitted Molly was right, it may have made Molly go back to seeing how things can get really bad for Issa.
Btw, how many of you were happy to see Issa thirsting for Lawrence and was proud when he immediately shut her down. "Yeah, we can hang up now." is probably the coldest line of the show so far.