Well I admit this is one of the few times on here CTE may actually be applicable after those brutal Cain fights and most of his fights since but in this case, if I recall correctly, (haven't see the fight since it happened), this reckless overhand came shortly after he hurt and dropped Francis with a slightly tighter over hand.
He probably figured if it worked once it might work again and might have thought Francis was still a little dazed.
As sloppy as the punch was though the nonsensical popping straight up 90 degree turn escape attempt was the worst part by far. All he had to do was stay low and continue moving forward to circle in behid after he got clipped and he could have bought himself enough space and time to regain his composure and footing while Francis was forced to break his own forward momentum and turn around.
There's a strong possibility that's easier said then done though after finding yourself overextended and off balance right in the path of a monster who punches you in the back of the head (legally) and temple with 2 shots you never saw coming in that exact same moment.
Being discombobulated and panicking in such a moment is probably a fairly reasonable and forgiveable offense, lol.
