Similarly, it is not uncommon for a sleep walker to walk out an open window or off a balcony

My boyfriend did this. I woke up just as he was trying to open the window (with the air conditioner in it). I asked him what he was doing. "I want to go outside". He was fast asleep. He is a sleepwalker. Ever since we moved in together, I sleep very lightly. Someone needs to keep an eye on him.

Sleepwalking Can Be a Walk on the Wild Side