Sherlock jumps- we see him fall. However, we don't get a continuous cut all the way to the ground- because he never hits the ground. Instead he lands in the handy rubbish truck parked in front of the hospital. At the same time a body prepared by Sherlock and Molly is dumped out of the truck onto the pavement. We see the truck drive away, taking the real Sherlock with it. Elementary ;)
The only odd thing is that hitting Watson with the bike doesn't seem necessary- it would be most useful as the body hits the 'ground', but I guess he was too far away/his view was blocked anyway.