It looked like he freaked out a little 'fuck I've hurt him, but what do I do now?'. Remember Harry going mental on the commentary but frank just seemed to stand back not knowing what to do next.
The first time Bruno fought him, he was the first boxer that actually "hurt" Tyson. Up to that point Tyson had looked utterly invincible and noone had even stunned or rocked him or even showed him to be human. Bruno caught him with an absolute beauty and Tyson was in trouble for a momemnt.
Bruno staying on his feet to a peak form Tyson was a massive night.
Then he recovered and destroyed him but it was first time in history that anyone had shown he could actually be caught / hurt.
The Collins, Benn, eubank (?) era was also wonderful to watch.