Don't be so naïve. Boris is pushing an immigration Bill through Parliament; watch PMQs and he dismissed the idea outright. Don't forget that not so long ago, Boris and his coterie voted against giving pay rises to people in the medical profession. This was no gracious climb down by Boris; he knew exactly what he was doing. The new Bill would have penalised the very two foreign nurses, who looked after him. Boris knew exactly what the evidence was; he was the architect of the Bill but he crumpled with the possibility of a Tory back bench rebellion.
The medical profession were given a very good 3 year pay deal in 2018, so I don't really know what you're on about.
Why is it naive to think he reviewed the evidence and changed his mind, I realize that you never admit to being wrong, but that is your weakness not Boris.