As a nanny who has been looking after children for 34 years, I have learnt that all children are totally unpredictable.
Almost 3 year old, very compliant and predictable, slept 7pm-8am without fail - climbed out of bed, went down stairs, pushed his high chair to the front door, grabbed keys from hook on the back door, unlocked front door and ‘drove’ mums car, she had only it a few days, never had a car before, charge loved ‘driving’ it. Had never left bed until mum or I went in. Didn't get up alone again for a good couple of years. Neighbour saw 3 year old in the car and knocked the door at 6am.
3 1/2 year - again very predictable, rule follower, put the new, totally adored kitten in the washing machine, shut the door, turned on machine, dad was in the shower when the water went cold so went to investigate, managed to get kitty out, child had been colouring in dad’s bedroom and painted the cat, thought dad would be cross so washed him!
15 month old twins - mum went to the bathroom, twins in the playroom, twin 1 got on his hands and knees, twin 2 climbed on his back and climbed over the stair gate and got a low stool pushed against the gate, twin 1 put their feet through the gate, climbed onto step and twin 2 pulled twin 1 over the gate. Opened the fridge and started eating a pack of ham. Mum had come back in time to watch the climbing over but wanted to see what happened. Twin 2 was a lazy arse, wasn’t walking, barely crawled, sat Buddha like chewing toys waiting for food!
3 year old - mum was in the garden hanging out washing, 3 year was watching tv, eyes glued, mum came back in to see child with a knife in the toaster, had climbed over gate, put some bread in the toaster then tried to get it out again.
When I was 2 and a half my 3 month old brother was asleep in the garden in his silver cross coach pram, I took him for a walk on the road outside our house, thankfully it was a very quiet road but it was also a 60 mph, winding country road! Luckily a neighbour saw and took us back home, there were 8 houses, set back at least 15 metres from the road and all houses had the kitchen at the back of the house and the front rooms were for special occasions (Christmas, Coronations and Jubilees!)
So I have learned that you just cannot trust young children no matter how well behaved they are. They watch and learn and then do something you completely don’t expect. Hopefully things will work out ok, you’ll have a bit of a cry and squeeze them tight but it doesn’t always end well.