So why turn up in an ambulance?

I'm watching the 7/7 inquiry, not that I expect to learn anything new about the motivations behind those who did it, but more to confirm just what a mess the initial response was, from the TfL "Power cut/transformer fault" which sent the wrong people to the scene to the Ambulance service sending an ambulance to the scene only for it to act as a liaison centre for other ambulances rather than deal with casualties.

BBC.

Firefighters at the Aldgate terrorist bombing were "hostile" and "quite upset", the 7/7 inquests have heard.

Paramedic Anthony Kamner was in the first ambulance to arrive at the Tube station after the 7 July 2005 attack.
He told the hearings that firefighters "did not understand the role" of the initial ambulance which was to report the situation back to the control room.

The inquests are into the deaths of 52 people who were killed by suicide bombers on three Tube trains and a bus.

Mr Kamner said the firefighters were "demanding" that he take some of the injured patients to hospital.
He told the hearings that he tried to explain that this was not his role, and that the firefighters were "not helpful."
Shehzad Tanweer, one of the four bombers who carried out the London attacks, blew himself up at Aldgate station, killing seven people.
The inquests have heard that a group of firefighters refused to enter a tunnel at Aldgate because of health and safety concerns.
Police Inspector Robert Munn said there was a delay as they tried to confirm the electricity had been switched off.

Now I know it was a difficult and confusing time for all, but surely an ambulance should be used for its purpose? The guys a paramedic, he should have got to the scene, made a quick assessment, then got back-up, then started triage and evacuation of the injured. I'm no expert of course and I might have this wrong, but surely one of the controllers at HQ should have been despatched to the scene once alerted to a serious situation to do the liaison thus freeing up a trained paramedic to do his job? perhaps it did happen like that, though there's no indication in the report to say that it was, just fire fighters getting annoyed because an ambulance was just standing there. Did people die because they were waiting? Possibly. Were more lives saved because a proper liaison was going on? Possible too, though why he needed an ambulance once he'd got there remains a good question, particularly if he wasn't there to be a paramedic.