Sorry about that, it was Corbyn and his stance on vaccinations and jab passports I had in mind with the fallen and hit one's head comment.
I think that a strange concatenation of circumstances has placed Johnson in a position where, for all the wrong reasons, he's forced to do the right thing.
That is, while he absolutely hates having to do it, he's more willing than otherwise he'd be to introduce these new restrictions, with the threat of more to come, because, if he has to have headlines about Tory MPs baying for his blood, it may was well be about doing the responsible thing and protecting the country rather than parties and lying about them, and who paid for his extravagant redecoration of the Downing Street flat, and the impending electoral disaster tomorrow in what should be one of the safest Conservative seats in the country.
It's his famous "dead cat" tactic all over again, but this time the cat gave one of its lives in a good cause.
It also helps, I think, that Rishi Sunak and Sajid Javid are both very much front-runners to replace Johnson, so it's very much in their interests that the NHS is protected, that the vaccination programme succeeds, because that's that the general public, as opposed to Tory MPs, are worried about, so they want to be seen as competent good guys while Tory MPs get angry with Johnson (whose problems with parties, and lies, and general mismanagement and corruption won't go away).
To be fair, if we have to have a Tory government, I'd far rather it were led by either Sunak or Javid than by most of the other potential candidates, since they're both very intelligent and able, which is a hell of a lot more than can be said for many of their colleagues.
They also have more or less coherent political and economic principles with which I don't particularly agree, but at least they've got some.
ETA: To continue my riff on Sunak and Javid, both of them made fortunes in finance and economic forecasting before they went into politics, and they made their money by taking projections seriously, even if what they predict is unwelcome, and understanding how to take decisions in a highly uncertain environment. This kind of complex risk analysis has been a major field of economic research, as I understand it, ever since Lehman Brothers.
So they know the number of lives people are gambling with if Omicron does prove as serious as it might well be and preventative steps aren't taken in time.