I can kill anything as long as I do not have to watch it suffer from my actions. I cannot watch anything suffer. (except wasps--not bees, but wasps. They hate me and I hate them.)
This is where I would hope that if a game official saw me do it, or there were other witnesses that called in and told the game officials that I had shot the animal and not tagged it, I would hope common sense and discretion would come into play.
I would seriously kill that bull as soon as humanly possible. I once watched a wounded (from a car hitting him) very small mule deer 2x2 buck sit on the side of the road for 4 days before a blizzard finally killed him. I can't get that thought out of my head. I was with the landowner and the property I was hunting was twenty miles away. The landowner told me that if I killed the wounded buck that I would have to tag it because so many people would see it happen. I didn't kill the little buck and eventually killed the largest mule deer of my quickly slipping away life.
No, I would not try to take the antlers. That would surely take away the common sense and discretion I would be hoping for. My actions would be purely ethical and humanitarian. And yes, I would keep my tag and try to fill it with a nice animal, and it would get the quick death it deserved. I already know what some will say about wounding the animal, but don't. I have NEVER, EVER wounded and lost an animal I have shot. Running 50 yards and dropping dead does not count as a wounded animal. Well, that is not completely true. I have wounded a fair number of ducks and dove.