Doesn’t really matter how they were dressed, and there are videos of them clearly dressed as hospital staff.
Either way, attacking a hospital without warning is a crime, doesn’t matter who you are killing inside it. Again you’re trying to invent a scenario where it fits your narrative, while ignoring the geneva convention.
If you want to start arguing whats a war crime and what isn’t, you’re going to need the document that outlines what’s a war crime and what isn’t.