Complex sentence: Asuka then had to stab the core with two knives (and kick one of them deeper into the core) to destroy it causing Sahaquiel to explode into a massive geyser of blood and floods a great portion of the city.
Split into simpler sentences: Asuka then had to stab the core with two knives (and kick one of them deeper into the core) to destroy it. When defeated, Sahaquiel explodes into a massive geyser of blood and floods a great portion of the city.