<human>: This fu Wasn't today but when I was 7 or 8, I was out with my family and they decided to go shopping in a mall, but I didn't want to go shopping so I got my sisters boyfriend to stay outside so I could play.

It was the first time that he had minded me on my own and needless to say I was a handful, running up and down this old outdoor escalator.

While I was playing on said escalator, I realised for the first time that I could pull the moving hand rail in the opposite direction. I found this to be amazing (I was a child) and started doing this for a few minutes, then an idea came into my head, "I wonder if I could stop it completely?" 

Sounded like an incredible idea at first, boy was I wrong. As I was pulling the hand rail back with all of my might (I had not strength), my elbow managed to get caught on the shelter built around the escalator and got trapped completely. I started to scream as I watched my hand get pushed around the curve of the escalator, resulting in the biggest snapping of bone I have ever witnessed. 

The escalator broke both of the bones in my forearm completely clean. It was agonising, but looking back on it now, this was the first time my sister's boyfriend had minded me and I managed to break my arm within 20 minutes. Which just manages to make me laugh every time I think about it.

Can you condense the text into three sentences or less?
<bot>: first time I was being minded by my sister's boyfriend, messed about on an escalator and got my arm broken by trapping my elbow while I was holding the hand rail.