4yo is not an infant. They will not drown in an inch of water.

I am working through a similar problem where my partner and I are not aligned on parenting and it’s quietly undermining everything we do. When you say “I told my partner time and again I don’t agree with soaking the bathroom floor” but you can’t reach a common ground, that’s a real problem. You didn’t snap for no reason, you knew something like this would happen and you feel ignored by your partner. Stop the buildup, you can’t stop the volcano erupting if you (both) let it get to that point