The hospital really needs to move the patients out immediately if the local military starts military operations from within hospital (which is basically a war crime).
Then, if the commanders force patients to stay by threat of violence to stay as human shields, that's a further war crime. The responsibility of casualties here is more with those using patients like this, than anyone else.
Typically because the cost of not killing the hostage takers is basically the risk of dead hostages. There's nothing else at stake. You can safely assume that the next plane full of hostages that has terrorists at the controls will be shot down.
I'm not really advocating yes or no to bombing hospitals or schools to kill terrorist leaders hiding within - but your assertion is false. We will kill the hostages. All actual breaches involve a risk of % losses and that's baked into the decision to go in. Just a person somewhere trying to make a decision about the best outcome, for the "greater good".
Then, if the commanders force patients to stay by threat of violence to stay as human shields, that's a further war crime. The responsibility of casualties here is more with those using patients like this, than anyone else.