I think that McCall was trying to emulate an opponent that they expected to tie up a lot. At points, when Tyson caught the McCall jab, it kept him back because it was a forceful punch. Even catching it stopped Tyson.
You can see some of Tyson's shortcomings on display. A number of times he made the move and didn't counter. He would slip and not throw a punch. And he would walk in with his hands up, not punching, and let the guy tie him up. I was suprised to see how straight he was standing at that point in his career.