I had the same issue. I ended up hiding on the side of the fridge or after I got the door open, mom would grab me before I could complete the ending. Ideally, I should have turned her off after you open the lock. Thanks for playing and thanks for the feedback!
Haha, yea, we suspected she could be hard so we did make it easier than it could have been. You can avoid the mom entirely by just walking along the wall :P
