You have a lot of good faith in what your bank would or would not do, and they have a conflict of interest: if they side with you, they would need to make you whole — out of their own pocket. The hospital has the opposite conflict of interest: they are actually interested in helping you — and charging you (or your insurance, or NHS, or somebody).
If you get your case against the bank in front of a judge, you need to prove your claim of an account takeover. The bank does not need to prove anything. If you haven't convinced the judge, no money for you.
If the transfer is instantaneous, the fraudster could have cashed out already from the other bank account. There is nothing in the other party’s bank by then.
The chargebacks in credit cards come mostly from the credit card issuer pockets, and are funded by credit card fees. Not the case with banks that don’t take any fees on transfers.
If you get your case against the bank in front of a judge, you need to prove your claim of an account takeover. The bank does not need to prove anything. If you haven't convinced the judge, no money for you.