Is it a good idea to blow hot air through drywall?

I have a small room with no windows and I want to cool it down. A friend of mine suggested me to get a portable AC, create a hole in the wall (drywall) and put the exhaust hose through the wall. This way, the hot air would exit the room and will be diffused in between the drywalls.

Seems like a good idea ?
What could go wrong ?