To answer the question, there is no way she has children unless she adopted. That's as butch as it get, from the rugby oversized shit, to the sweat pants, to the running shoes.
If I were driving that car, I would have milked that situation for EVERYTHING! If she wants to walk away after screaming, elevate the situation again! My god, she is at her breaking point, so a slight cooling off period has little to do with bringing that water back to a rolling boil. Peel out, then reverse back and ask what she thinks about that. Jump the curb and do a quick lawn job in front of her. A few doughnuts in the middle of the street. Maybe sit there as she's screaming and just keep revving the engine (not too high, because you want to hear her screaming). Bottom line, a butch like that has to be fucked with.
Side note: you have to address her as "Tammy" when you are laughing at her. Pretty universal dyke name, and that will surely escalate the situation for the lolz.