He definitely did tailgate the ambulance, which was responding to a suspected heart attack. The barriers were opened for less than a minute to allow the ambulance in, and he followed it. Now, he might well not have known he wasn't supposed to go in there and that is why it's important that the sequencing is properly understood.
If he went in and hit someone or someone's with his car, then the attack on the car happened that quite different than if he was sitting waiting for the crowd to disperse, and was attacked for no apparent reason.
Thing is, off his tits on coke and now charged with attempted (edited) murder means he's bolloxed, and rightly so.