I agree it's unlikely Marten's mom will hurt Dora, but I'm also not sure they're going to have a serious heart to heart about it. This is all supposed to take place in the time of a plausible phone call during dinner, remember? My vote is for either a brief dropping of warnings or wisdom on Dora and limiting her involvement to that, or her and Dora agree to talk later--in some arena where they can be a little more equal, instead of Dora just having a really serious and intimidating conversation just sprung on her. Although if Marten's mom thinks that her dropping by the shop and confronting Dora when she was supposed to be taking a phone call is going to stay a secret, she's kidding herself. And Marten will be mad. If even she didn't know he was going to see that as a major boundary-crossing, she wouldn't bother being sneaky about it--and trying to do it when Marten couldn't follow her even if he was suspicious, because he's a little tied up with Hanners and Tai at the restaurant.
Or, Marigold comes in and is all HEY GUYS WHAT'S UP and awkward ensues, in which nothing goes the way anyone wants it to.