I think mom should be more ashamed.
Let the jury recognize that mom's story implies the toilet seat was up. Thus, she either witnessed the cat playing with a live mouse and did nothing until the cat, allegedly, dropped said mouse into the toilet, or it was more likely that a thirsty mouse fell in.
We can also assume that mom was too frightened to save the mouse and also did not have the courage to flush it and end its suffering faster. If either statement were true, mom should have been able to use the toilet.
All we can be certain of from her own confession is that she is a subhuman mutant that pisses in the tub.