You are a lucky man....Congrats on a good retrieval. I've seen a couple elk lost taking a quartered to you shots like that and jumping on a blood trail too quickly.
I had it happen myself one time unintentionally. The elk was dead broadside & it turned slightly just as i loosed the arrow. Fortunately the leg was forward and i missed the shoulder blade and caught the lungs, but the exit was ugly and my fletching was green and red. I went back to camp and ate breakfast and waited on my hunting partners to return to camp. We found it in a creek bed still alive after a 4-5 hour wait, but it was too exhausted to get up on its feet.
the ones my buddys lost, they found them bedded down and after they jumped them, they didn't leave a blood trail at all.... i've seen the same thing on deer lost.... Its a tough call sometimes on how long to wait. Kirk