So parked cars affect firetrucks or do they jump out of the way?

I would say the hospital would sell it to a debt collector in the UK. If it gets to court you could argue incorrect jurisdiction as the contract would have started in the US but that’s risking a lot on a technicality. You would also need to fork out for a solicitor, barrister and court costs. I think they did the right thing in shaming the insurance into paying rather than fighting the debt collector who has no shame.