I'm thinking that at the end of the song, he reviewed his performance, decided it did not meet his expectations, and realized that the best possible solution would be to throw himself through a window. 
 
I admire his commitment to excellence. 
 
It's also a great way to tell the rest of the band, "I not undoes the not standing undown the what hey not why, no?"

Sometimes the answer is just sitting there right in front of you and you miss it! 

craigb
Sometimes the answer is just sitting there right in front of you and you miss it! 

Or smell it, as was suggested in another comment?

He looked drunk as a skunk and should not have stood up.
 

Query:
 
If a drummer falls out a window, but nobody hears him swear when he hit the pavement on the other side, did he really make a noise, other than the floor tom flying off-stage?