Parent A was supposed to be watching toddler in the living room while Parent B made lunch for toddler in the kitchen.
Toddler got out of open patio doors in living room onto a raised wooden balcony where there are steps that toddler could have fallen down.
Parent B went back into living room to ask Parent A something, spotted toddler outside and asked why is she out there? Parent A was sitting scrolling on their phone, jumped up and said they "hadn't realised".
This has caused Parent B to feel stressed and upset that toddler was not being properly watched while they made toddler lunch. This is because of the potential that toddler could have fallen down the steps outside.
Parent A argues that it was Parent B's fault, however, because they opened the patio door a couple of hours prior when toddler was sleeping to let some air in as it was hot in the room.
Parent A believes that because Parent B opened the door, they are responsible for what happened.
Parent B argues that Parent A was the one who was supposed to be watching toddler while they made lunch, and therefore they are at fault for being on their phone and not properly watching toddler.
Who is at fault here?