I've found them a long ways down in the worst crud and down fall just pushing with their back legs. I've seen a cow with two broke shoulder get her rear end under her jump forward then repeat. Had a doe antelope do the same thing, blew up out of the bottomed of a little draw with both front wheels out and getting along on her back feet good enough I had to run her down after realizing what I had just saw go by me.
I've now seen two elk healed over with an arrow side to side above the lungs in the pocket.
Cut a LOT of elk with healed shoulders that were shot, especially bulls, shot a cow running through the timber and when we cut her the top of her spine over the shoulder was blown of and healed over.
Can't count the number of broad heads I've found in elk, stuck in shoulders, spines, hips.
They can be resilient but most certainly not tough to kill, a white tail with their heart shot out will make it much farther than an elk will!!!