The knife trick will work, but you better be having your mind set on completing the job. I remember the first time I tried it, on a spine-shot doe, I was a bit timid at first. The deer bit my jacket. Either you jab that knife down through the deer's throat like you mean it, or shoot it again. Tougher to stab through the neck than I would have thought. Had to do it once since then and it was easier for me because I remembered the prior scare.