Just out of curiosity, has anyone looked up the rest of the lyrics for Sherlock's "If I've got you" song?
Baby, if I've got you,
I don't need a parachute... (Parachute by Cheryl Cole)
Now I don't think he puts on a parachute...but I did wonder if the Homeless Network could catch him on a silk and bundle said silk into a laundry bag...
I quite like the pulse stopping (ball) theory and the loads of people as accomplices theory for the rest of the explanation.
Also, to respond to the above, I'm sure I read somewhere that it was Ben Cumberbatch on the floor/falling/trolley. I know he did his own stunt for the scene cause I watched the 'filming of' bit. So whether it looks like Sherlock or not, it is 'him'.