All right, here are some guidelines for the staff/military reaction to the food fight:
1)
Those who are actively attacking nurses or soldiers: the nurses will likely be told to get out of the way by the soldiers, who will then actively engage the patients in a fight. This means fighting back (either hand-to-hand or blunt hits with the butts of their guns) until the patient is beat down/unable to fight back. These patients would then be taken to solitary and given a strait jacket, the whole deal, because these guys aren't playing around. Solitary will last at least one shift, but could also last longer as you please.
2)
Those who are throwing food: so long as they are only tossing food around, they will only be sedated, either by a nurse or a soldier who's been given a syringe by a nurse, depending on how intimidating the patient seems. If they allow themselves to be sedated, that will be all, but if they fight back, go to step 1.
3)
Those who try to sneak off will be able to make it out of the cafeteria, but will be apprehended in whatever room they move to. For example, if they go to the Sun Room, a soldier will approach them there and basically stop them from going any further. If they give in, nothing will be done to them; if they put up a fight, they will be either sedated or physically engaged depending on how severe their reaction is.
4)
Those who stay out of it and just try to lay low will be left alone and will be considered well-behaved. Good for you!
In any case, at the very end of the shift the soldiers are going to probably get fed up and release a whole bunch of tear gas into the cafeteria to disable people, so look forward to that!
NPC mods are not needed unless in special cases, or for someone who is particularly persistent. Feel free to write this all out with your thread partner as works for you. And ask questions if need be!
Then the shifts will continue as planned, though some characters will obviously be in solitary, and there will be other consequences.