Many years ago my brother and i used to do the ocasional window cleaning job for an Asian man who was called mr Patwa.
He used to look after the stone in some very upmarket houses in central London, and he would use us to clean the windows when necessary (he would talk to us like we were sh**t, but paid good money)
One day he asked us to clean the windows on this huge house in St Johns Wood London. We arranged to clean the windows at the same time as he cleaned the marble floor. After about 2 hours we were cleaning the windows upstairs while he was using a rotary machine on the ground floor marble. All of a suden i heard a loud bang and a scream, so i had a look downstairs and Mr Patwa was sitting with his head in his hands and shouting to himself, his machine had crashed into a full lenth floor to ceiling mirror and smashed all over the floor. The customer was very very sad.
This was over 20 years ago, so i am not sure if it is the same guy.