Wow, that's a lotta war crimes. I think I count at least 5 different ones committed. Multiple counts of Perfidy, attack of persons hors de combat, multiple counts of attack of civilians/civilian objects, violation of rule 14 on proportionality of attack, violation on rule 15 on principle of precautions in attack.
Also, gosh wonder what would happen if you pulled a gun in a hospital in the US, which theoretically isn't even an active war zone. I've been in an American hospital twice during an active shooter event and the shooter got smoked both times before cops even set foot in the building.
Walking into a hospital dressed as a doctor and smoking three security guards is not the badass military op you think it is. Three patients, even more despicable.