DeerandbearhoG

Ok Ill tryn to make this short. I get to my public land spot well before light on opening day. Another guy musta come in behind me without me noticing ,say about 100yds up hill from my position, about 7am to my surprise I heard his rifle crack, then again a few seconds later.I looked behind me and saw a decent buck stumbling, but running pretty fast downhill about 40yds to my left. I wasnt sure if he was hit or just stumbbling on the rocks. He was headed for the a steeeeep draw, and I wasnt sure if I should do the guy a favor and drop him before he made it any farther down. Before I could decide he hung a right and ran straight for me! He cleared a deadfall only a few yards from where I was sitting, and I dropped him at 10feet! I dont even remember looking through my scope, all I know is 1 more second he would have literally ran over me. The guy came down a few minutes later. He said his 1st shot hit a branch but he thought his 2nd was settled pretty good on the deers right shoulder. He was shooing a 30.06 but we couldnt find even a small hole anywhere near where he said he aimed, all we could see was the hole in his chest from where I hit him head on, and what I thought was the exit since there was a ton of bloody back splatter right where he laid. He was nice and said it was clearly mine and went on his way,but I felt bad. I dont want to take another guys buck, but I didnt know what else to do so agree and shook his hand. Well after the guy left, and I finished dressing it out. I did notice a small hole in the deer back right above the spine which seemed odd since at the angle he was at, it shouldve come right out. Then I was really shocked to find a pretty good blood trail up the hill from where it came as I dragged it out. when I got home I started skinning it out and found a huge hole in the deers back and even 2 vertibre taken out, then I found my 7mm bullet loged under the skin right next to the exit hole, which i guess would explain the back splatter? I figure he shot high from about 30 yds uphill from the deer, his shot hit the right side of the spine and deflected down the inner left side of the ribs, Im guessing this wouldve been fatal but the deer would surly went a good ways into some rough terrian maybe never found. My 7mm08 destroyed the right shoulder blade and blew the heart to mush. I still feel kinda bad that I took another hunters fatally hit deer, but I really didnt have a choice to shoot, and I didnt even know he was even hit till the guy left. As I drove away I saw where he parked I was tempted to leave him a note saying he could have it but by that time I had tagged it and spent 2 hours dragging this thing 1/4 mile uphill so I kept driving LOL.For all I know he coulda killed another buck that day. Still feel kinda bad though. Thoughts?