Trapped in the bathroom

Sunday evening, after bathing for B2, I found the two of us locked up in the bathroom! We couldn't open the door from inside, neither could B1 or hb from outside. The door knob of all our bathrooms are those typically meant for bathrooms,with no keys.

Hb has to climb through the tiny window, from kitchen's yard,used screwdriver to dismantle the whole knob and lock to get us out.

After the incident, I was telling B2,"we were locked in the bathroom, the door is not working.Luckily daddy saved us out", then sang to her "Daddy is a hero.....".Guess what she sang after singing Daddy is a hero??? "I, Bertina,super hero!"

I can't imagine what will happen if hb is not at home.How am I going to save myself out?

After this incident, Hb put a screw driver in our masterbath,just in case.We also told B1 not to lock her bathroom door when she bath in her attached bathroom.