I had two such things happen to my youngest.
One I had an emergency and put them in the backyard to play. (should have been a padded cell)
They were 4
I said, 'now mom has to instruct the construction workers for a min while they tear out the carpet...stay back here and DON'T CLIMB THAT TREE!'
What do you think they did?
Took off their shoes (which makes feet slippery), and climbed the tree. Thing 2 slips, lands with a stick up her leg almost in her artery. This happened within 2 minutes.
Happening number 2.
She is 8 yrs old. We have a pool...I usually watch them through the kitchen window while I am washing dishes. Well I can't see when your swimming under water which they did alot as they were/are excellent swimmers. I had told her many times, don't swim through the ladder, your hips are about to start expanding and one day you won't get out.
What do you think she did?
(she was alone in the pool at the time.)
I didn't even notice this had happened and she didn't tell me until LAST WEEK. She is now 20.
She said she almost drowned, she was about to take in water when she finally wiggled out of it.
I remember doing the same thing many times....do exactly what mom tells you NOT to do.
Most of the time I got away with it so I stopped believing her (just like my kids did me) and thought she was over reacting.