When the acute psych unit I used to work in moved to new premises, we were assured that all the glass in the internal and external windows was unbreakable. Within a couple of months, a man managed to launch himself out of his bedroom window after breaking it with a fire extinguisher, sustaining severe head injuries and ending up a double amputee and a patient hoyed a chair through a window into the staff office, sending shards of dagger-like glass a foot long flying into the room, narrowly missing the three people who were sat in there at the time. Nothing seemed to happen to the company who had done such shoddy and dangerous work.