Imagine
Budget cuts to the Defence force forced the training team to start doing mock combat using no explosives, guns, or basically any equipment what-so-ever, so when it came to a training scenario, the Sergeant in charge tells his recruits that they are under imaginary fire, and what do they do?
So all of the recruits except one scatter and get down behind "stuff", and get into returning fire positions.
The Sergeant notices this one recruit standing out in the open, quite relaxed and unfazed.
Yelling, the Sergeant asks, "What the devil do you think you're doing? You're under fire!"
So the recruit takes one step to the left and remains still.
Now the Sergeant's really annoyed. He yells again, "What the Hell are you doing? You're under imaginary fire, take cover!"
The recruit turns to him and replies, "I'm taking cover behind this imaginary tree Sergeant!"