Especially since they didn't know how many more crystals Zhou Tian had, if they allowed Zhou Tian to continue like this, even if they weren't killed by the weapon in Zhou Tian's hands, they would exhaust their already limited energy in attempting to resist the explosion of the crystal bombs. Once their energy was drained and they were expelled from this world, their mission to descend to the Lower Realm this time would still end in failure.
Undoubtedly, such an outcome was something the deities could not accept. For this reason, after witnessing the destructive power of the crystal bombs, they dared not let Zhou Tian continue to detonate such weapons. Thus, when they saw Zhou Tian looking set to detonate another bomb, they were frightened and those two deities desperately took action to prevent Zhou Tian's actions.
Sadly, though the performance of the two deities was quite fast, the speed at which Zhou Tian detonated the crystals was even faster.