As long as that mission is purely transport and no patient management is required during transport, this is not a bad idea for rapid evacuation of casualties from the battlefield.
We've seen some UGVs used successfully in CASEVAC in Ukraine.... but outside of a battlefield where people are explicitly looking to blow up your ambulance, I don't see some big quad copter making any immediate civilian EMS use... Maybe some niche cases... but how is it going to load a Patient by itself? You're still going to have to dispatch a ground crew to properly load and secure anyone in this thing, which kind of defeats the whole purpose of a remote/autonomous drone flying in