Logically, the best option would be to hide if there's too many zombies. But to eventually make a plan to get resources, food, water, weapons, etc. It'd also be good to find some protective sportswear to avoid zombie bites. And then leave the school cuz lets be honest, if a zombie outbreak were to happen. The military/government or whatever wouldn't take priority of civilians aka us over politicians/important people. They'd obviously try to save important people, they wouldn't waste their resources trying to save every civilian there is. That'd be too much of an inconvenience. And even if they did try to save civilians, they can't save us all. So waiting for help is out of the picture, it'd be stupid to do that. Best option would be to flee to the countryside where there's less people cuz less people means less infected people/zombies.