@AWP
Yeah, pretty much what everyone here said. Basically, the Army was the lead component (with the British) for MEDEVAC throughout the nation. Before the FRAGO MOD 4 was dropped, we (AF Rescue) shared the pie because there were just too many missions to go around.
So, from a tactical standpoint- someone gets injured. 9 line hits wherever the medevac/British MRT/AF PJs are. Back in those days they were calling them "Alpha, Bravo, and Charlie", but in the actual terminology those were URGENT SURGICAL/URGENT, PRIORITY, and ROUTINE patients. Alpha's were essentially immediate launch, Bravo's were within 8 hours, Charlie's you had 24 hours. They did this weird thing where they would call things "Tactical Alpha's" for a bit too. If a team went on target and some dude rolled his ankle or took a casualty that would affect the mission, they'd call MEDEVAC to take that dude off target. They weren't actually an URGENT/URG SURG, but they were slowing the team down, so they'd have to go. Those were always suuuuuuper sporty, for whatever reason.
There was *sort of* a system for which platform got which patient between DUSTOFF, PEDRO and MRT- but it was ran by medical nerds and pilots and to be honest, they didn't do a great job. Every deployment I had, it seemed like I was fighting some J3 type that would send us to go on a patient transfer and send the MRT 47's into a hot LZ... it happened way, way too many times and I don't want to murder anyone today, so I am just gonna move past it. Some days it was just "next up", but some missions it was plainly apparent that shit was about to get sporty, so they'd send us. We had a great relationship with the MRT, and the architecture considered the MRT a "flying role 2", or an FST-like entity because their docs could do invasive surgery on the 47, so sometimes a patient would obviously need surgery on the bird, but it was too hot, so the PJ team would get on with the Brits.
As far as "where did everyone go", it was pretty well covered above. There were a metric shit ton of FOBs around, and they all had some level of care they could provide. So lots of times it would be "medevac this dude off target, stabilize them enough for further transport, get them to BAF ASAP, further stabilize, then out to Germany and back stateside.
Obviously, when you were out of BAF, everything was a smash and grab job to get back to BAF. If you were at Kandahar or Bastion or J-Bad or whatever, you'd have to figure out how bad the patient was, who could fix them and where to take them. Neuro and burns were only at BAF for a while, I wanna say the whole time.
It got a little wonky when it was a partner force; out of BAF/Bastion, you'd basically take them to their own hospital, like Lashkargah. This was always weird because MED ROE was restrictive in who we could pick up, where we could take them, etc. We had to take people we *knew* weren't gonna make it unless they went to BAF, but they were Afghani, so you basically landed at Lash and wished them luck. Americans also *NEVER* went in the hospital for security reasons. The docs or nurses or whoever they were would come out with a gurney, sometimes a rickety ass wheelbarrow, take your patient with absolutely zero handover, and then we would bounce.