@Babyroobs - yes, in theory. Happens not uncommonly during a normal winter. And it works well.
But hospitals in Sussex, Kent and Essex are filling up. Hospitals in Suffolk and Norfolk are cancelling anything non-urgent. The surge of cases in the East of England means hospitals there are struggling with massive staff shortages.
I don't know about hospitals to the north and west of London, but can't imagine there's much difference.
Which means it's only a matter of time til we run out of places for those patients to be sent.
And the ambulances that would transport those patients are sitting outside A+E with patients in them they can't unload. Or, if they're driving a patient 3 hours up the road to a hospital with space, and 3 hours back, they're not out picking up 999 calls. Calls which, in London, are up 50% on normal. So the last think you want is ambulances tied up transporting patients further and further to find a bed.
One major incident in one hospital is neither here nor there. But slack in the system as a whole is fast running out.