There is a rather stark difference between your idiot mates drawing a dick on your forehead after you've pasted out drunk and having medical professionals mess around with someone's unconscious body.
A more apt comparison would have been drawing on a co-worker's face while they're asleep. The point remains that these sorts of pranks happen countless thousands of times each year without the need for lawsuits. It's very difficult to demonstrate emotional harm and most of the other accusations are excessive or ridiculous (I mean, sexual harassment... really?). Certainly there was a significant breach of trust that warrants an official warning, and if there is a history of this sort of behaviour then further action should be taken, but I don't think it warrants ruining careers that took decades to train for. I don't see any benefit to society in firing the employees involved or awarding massive financial compensation.
Let me just be clear, I'm not defending the actions of those involved as I think what they did was wrong. However, I think it would be just as wrong for those involved to lose their jobs or for the hospital to be saddled with massive legal costs.