The Beetle King was still recovering from the insane amount of pain that Mako had induced into its body through its crushed eye cavity, and it was expecting Mako to do the same given the amount of electricity he had just absorbed into his system.
unfortunately, one of the effects of Rage Mode is that decreases Mako's intelligence temporarily, not just his intelligence overall, but more specifically his logic and reasoning center of the brain.
Even though he had received a decent amount of damage from the Lightning attack, he immediately brushed it off as if it was nothing and prepared a counter-attack.
Any sane person would call Mako suicidal, but that was just how Rage Mode affected his thinking. He was like a wild beast that only knew how to ravage and destroy and wouldn't stop until all his targets were absolutely crushed and defeated.
Despite being in so much pain the Beetle King had to respond as it couldn't take much more of Mako's full-range fire attacks.
