If he had been stabbed, he might not have had the opportunity to shot the ahem, perp.....
Oh I think he very well might have. He was backing away as the thug was stabbing at him, at maximum extension.Note that even though the knife hit the battery compartment, the phone was still operable and used to call 911 after the perp was either down or at least heading for the tall grass. He would have been cut, but probably not all that seriously, certainly nothing to take him out immediately. It was on his left side, he used his right hand to fire the pistol, so even if stabbed in the left pectoral muscle, or thereabouts, he very likely would still have been able to shoot. Of course his adrenaline level would have higher, and he might have shot the "suspect" multiple times.