Nothing is a certainty. For all we know, a brush with mortality might trigger an intense re-evaluation of his life and lead Trump to withdraw from public life and pursue spiritual enlightenment through religion, diet, and raising fancy dogs. Speculation may be entertaining but it's hardly sensible to proclaim one possibility out of a range as being certain.
Here's another possibility, since we're playing this game: raising a fist while being walked off a stage only proves a person wasn't killed immediately by a shot. The injury may actually have been more serious. When you see Trump walking around and talking several hours from now you can dismiss that possibility, but for all we the public know he is right now in an operating room. Not all headshots are instant death, the human body is more complicated than video games make it out to be.