Seen/been apart of something like this on deployment when i was active duty. After months of training for doing wacky surgical interventions with a surgeon, and resus for 2 months, i had a mega hard-on to see someone cross clamped pre-role 2. Christmas morning when it happened. Outcome; Survival to role 4, alive one year out.

R2LM & like elements train to do in-field/in-transports basic surgical procedures. Resus. Thoracotomy w/ cross-clamp is one of the tools in that tool bag to create a nice back-stop (REBOA is starting to take over now). Sticking a foley into a heart perforation/tear, and inflating the balloon is another trick to buy some time.

Shockingly you dont really need a lot of equipment to do this. You need a surgeon/ER doc willing to do it, and an assistant who can help. Thats the bar for entry.

Right person, with some betadine, 10 blade, rib retractors, and a "big-ass-clamp" can do a lot at the right time.