So, it was right after this that JFK received the fatal head shot, and then Greer, finally, took off. But, phone calls had nothing to do with it.
But, since Roberts said that he called Lawson, let's see what Lawson said.
I noticed Agent Hickey standing up in the follow-up car with the automatic weapon and first thought he had fired at someone. Both the President's car and our Lead Car rapidly accelerated almost simultaneously. I heard a report over the two-way radio that we should proceed to the nearest hospital. I noticed Agent Hill hanging on to the rear of the President's vehicle. A motorcycle escort officer pulled alongside our Lead Car and said the President had been shot.
First, this thing about Hickey standing up with the automatic rifle. We have an image of him holding it, but not standing up. He was a tall man, and he definitely was not standing up there.
So, at some point was he actually standing up in back? I don't know, but if he was, it had to be before the cars sped off. You can't tell me that he stood up when the car was moving fast; that would have been dangerous. Plus, there was no reason to do it. So, did he stand up in the car on Elm Street when things had come to a stop or nearly so during the shooting? I don't know, if he did, that's when it had to happen. But, notice that Lawson said that he heard a report over the two-way radio that we should proceed to the nearest hospital. That seems rather half-hearted to me. It's a horse of a different color than saying that he spoke to Agent Roberts on the car phone, who ordered him to drive fast, but not too fast, to the nearest hospital. So, I do not see this as being a confirmation of what Roberts said. Moreover, the crucial thing is the timing. When was the call made? Roberts claimed to make it after the last shot, but we can see him talking on the car phone in the Altgens photo which was taken well before the last shot, at a time that Kennedy had not yet received a lethal injury.
Roberts was talking on the phone right there. You notice the two agents peering back at the TSBD, and that peering is what made the Altgens photo irresistible to the plotters. Without that in the picture, they may have just destroyed the Altgens photo- considering that Oswald was in it. But, they couldn't resist the "agents peering back at the source of the shots" angle, which is how the caption read. But, the irony is that what they appear to be peering at is Oswald in the doorway.
But, the point is that JFK had not yet, at this time, received a fatal strike. At this point in time, he may have been able to survive and with all his mental faculties intact and with the capacity to resume his term in office. So, what should they have been doing? I don't know for sure what their best option was at that point to try to save him. How about screaming at Greer to step on the gas, to floor it? That seems to me to be the most urgent need. Just get the hell out of there.
But, my main point is that Lawson made a vague reference that may be seem, to some, like a confirmation of what Roberts said, but if so, it is baffling that he didn't state, in plain English, that Agent Roberts called and gave him an order to rush to the hospital. If he spoke to Agent Roberts during the shooting, why didn't he say so?