Please comment your own theories.
I reckon it also had something to do with him saying 'stay exactly where you are' because the bike came and knocked him over and the truck obscured his view...and then when he took Sherlock's pulse he was super dizzy (and in shock) and Sherlock did say that taking Mercury slowed your pulse, so he probably took some of that. I think the people who crowded around him where in on it, and they took him away so fast...he might have asked for help from the homeless network.
...And then there's Molly.
Well because of the whole 'I need you' scene. She might have given him all the equipment he needed and so forth...
I definatly sure Molly's in on it. Or I might just want her to be in on it. Either way, she's a major thing I think is involved with it.
The bike also. The bike had to be involved. But I never considered the homeless network before. I thought they might, but I was never sure. Interesting idea. Could be. But how would you stop random normal non-involved people walking down the street?
Mycroft could have been in on it too, he could have set it all up for him...
Really? I didn't see that!