This is basically what would happen if Doyle wasn't killed and they drove off with him.
"Go! GO!"
Scarlett slammed the accelerator, escaping from their predators; and they were human. The infection hadn't spread to them, wearing their gas masks and small armouries around their belts. No blood was oozing from their eyes, their mouths weren't disfigured, and they had no longing for human flesh. And yet, they were hunting them. Scarlett drove through the misty streets, avoiding the lashings of fire and any Infected they may come across. Sergeant Doyle hastily barked directions, leading the remaining four away from the danger zones and protocol.
"Left! There, see the end of the street? We'll be leaving the centre of operations! Right! Yes!"
The car was now on a dirt road, a piece of land, overgrown with crops, lay beside them.
"Doyle? Where do we go now?"
"Anybody like the seaside?" he chuckled, "We don't have anything more to do. The infection is contained now."
Even though none of them had dared to look back as they escaped the city, Doyle knew that the military would have done the job they had planned to do all along. It wasn't as if they had planned to kill the thousands of people that had returned to England, it was just that there was always the chance of re-infection lingering over them.
The city would be decimated now.