I agree with you to an extent. It does seem extremely odd that she would just forget about it. Why didn't she set a timer on the oven or on her phone? It does seem like the kind of thing that might be a recurring issue with her.

That said even if it is the 'straw that broke the camel's back' the reaction described by OP is really bad. She locked herself in her sewing room crying? Was she scared of him? Was his reaction so violent that she had to hide and lock the door? And he turned up the volume on the TV so loud as to drown her out? That's absolutely terrifying.