ATC Controller reported a flight of two military trainers exited their training route prior to the coordinated fix and were flying below the Minimum Vectoring Altitude.

Narrative

Flight of 2 Aircraft; Aircraft X and Aircraft Y was coordinated to be in training route and exit at XA00z at ALT 090. Radar ZZZ received that information from ZZZ Center and told me about it as I was working the ZZZ sector. Sometime later; an IFR aircraft inbound to a satellite airport was coordinated from ZZZ1 sector to enter my airspace at ALT 083 for terrain. The flight path and altitude were in conflict with the exit point and altitude with training route; so I told the ZZZ1 Controller to assign heading 320 to deconflict. When the satellite arrival was in my airspace; I had descended the aircraft to 080 and had them on a heading to parallel the protected airspace of the training route. The MVA in the area is 078. ZZZZZ1 is the exit point of training route and where I was expecting Aircraft X and Y to exit. That point is also in ZZZ1 airspace. I noticed Aircraft X and Y targets spilling out of the lateral confines of the training route and tracking westbound toward ZZZ airport. The altitude indicated approximately 044 and they were within the 078 MVA. Aircraft X and Y then radioed my UHF frequency looking for Approach Control Service. I was never advised from ZZZ1 sector of a handoff or any status change to the training route. This happened around XB53Z. The point Aircraft X and Y terminated their training route was around ZZZZZ. I was expecting them to go all the way to ZZZZZ1. I instructed Aircraft X and Y to ident. I radar identified the flight; advised them of IFR traffic overhead at 080; and that they were currently in a 078 MVA. I issued traffic to the civil aircraft before Aircraft X and Y radioed me; when I observed the targets spilling out. The speed of Aircraft X and Y and their rate of climb was not a safety issue with the other aircraft; but it was unsafe for that flight to exit the training route early and expect IFR service at those low altitudes.After I established radar and radio communication with Aircraft X and Y; I advised ZZZ1 sector that the flight was with me and on their way to ZZZ airport. ZZZ1 flashed me the data block at that time. I received a position relief brief and advised the incoming Controller of the situation. At that time Aircraft X and Y was above the MVA and being sequenced to ZZZ. Suggestion: ZZZ Center needs to confirm the exit point of ZZZZZ1 to the pilots of the aircraft operating in the training route before they begin the route. If anything different is going to happen; then ZZZ needs to be made aware immediately so that we can ensure that proper separation is maintained from aircraft and terrain. If ZZZZZ had been coordinated earlier; then I could have had the satellite arrival at ALT 100; and also made sure that Aircraft X and Y didn't exit the confines of the protected airspace until at an appropriate altitude. This situation was very dangerous and not the way we should control our airspace.