Curse Amplification
Eren had been focusing on Bloodhound. The wild instincts ravaging through his body, thanks to Curse Manifestation, didn't affect him much. However, his Curse's instincts were potent enough to influence his mind to a certain extent.
Eren gained tremendous strength, enough to fight on par with the Hyumans who'd practiced the Primordial Bloodline technique to the peak. Still, the downside was that his mind focused solely on his enemies as long as the strongest form of Curse Manifestation was unleashed.
He narrowly missed the moment Bloodhound decided to change his target to hunt down Michael. Even though Bloodhound would prefer to purify Michael and bring him to the Parliat, where his talent would be assessed and his starting position in the ranks of the Supreme Human Alliance determined, he didn't have an issue killing Michael either.
It was better to kill a future enemy if he couldn't salvage him anymore.