Prime example of going into quick, I still run by the rules of shoot it pour a cup of coffee and roll a smoke and when it’s finished flapping about going and sort it out!
No, it wasn't an example of going in too quick on this particular occasion, but it it is a good example of what an apparently incapacitated deer can do.
(Like you, I always crack open my flask and smoke a roll-up before approaching any deer I've shot. The one that headbutted me was not a deer I'd shot).