Mia really didn't want anyone dying, especially inside her, but there was something primal in her that did not want to surrender its very large meal. So she manages to compromise, keeping the meal inside, but holding back the accumulating acid. Alyn would hear this as the acid stops flowing, mia offering "You can join them in there if you want, but I will not give them up." She wants more, the predator within not abiding by the limits of her less-than-formidable body, and wanting to have an even larger belly, all the more for her.