BOOM BOOM BOOM BOOM BOOM!!!
Rui blasted Ieyasu with powerful blow after blow as he deactivated Megamind and activated Hypertrophic Surge and Neo Godspeed instead. The tachypsychia and prolonged use of Megamind had strained and stressed his mind, not that he remembered that. The hypnotic amnesia had already stressed his mind even further, thus he truly could not afford to put his brain under any more pressure.
Before sealing off his memories, Rui had implanted a suggestion in his head that conveyed the urgency of winning the battle as soon as possible since he wouldn't remember why after he lost important memories. He couldn't allow his hypnotic amnesia to sabotage his own strategic considerations.
On top of that, Adaptive Evolution was dynamic and ever changing. The information load of the battle had lowered significantly, thus he no longer needed the extra cognitive power of Megamind to defeat his opponent.
