I don't know about the "no instincts" comment, but JJT is right in that if Austin ran to the pylon he would have scored the TD. He had the safety beat (#36, Nick Collins) and turned it upfield rather than continuing to the pylon.
I noticed it when it happened during the game, and Michael Irvin gave Austin some ribbing on the very same thing on his radio show. Austin laughed before Mike even mentioned it because he knew it was coming, and he knew that he made a mistake there.
No biggie since Barber scored anyways, but what if Barber had fumbled? What if we had to settle for a FG there? It was a mistake on Austin's part, and I'm sure it's something he can learn from.
And yes, this is probably nitpicking...