This, the idea is great, but when it comes to people who starved/dehydrated or got in a fistfight(that ended in more than just a KO)2, I'd say a hospital visit wouldn't be needed. For RP, anything more than that (gunshots, accidents, BATtery, etc.) would need a hospital visit. The only issue is with everyone that dies this is almost impossible to do, otherwise one person would get revived every ~5 minutes depending on where they died.
Though with robberies, or any situation where someone is downed, I'd say they can be rev'd but must sit out for the remainder of the situation until they visit a hospital. For instance, if a cop/robber is downed at robbery (even from dehydration as it would take time to be back to 100%), EMS can rev, but they can no longer be a part of the instance or any followup, unless they are taken to a hospital - which would be at the discretion/safety of the EMS. Such as if a robber is shot, the EMS will not take him out of the UD and bring him to a hospital as the cops would arrest him outside; or if a cop is shot inside UD and robbers have people positioned in the parking lot, the EMS wouldn't risk going out to bring the cop to the hospital.