The crystal rod Gudora created was through his last bit of strength. Hence, it wasn't powerful enough to shatter the Prana Bomb walls.
The moment they made contact, all the Prana in it was absorbed; hence, the crystal rod couldn't even dent the Prana Bomb walls. As a result, even though it was a perfect fit, spanning exactly the diameter of the pit, thanks to Gudora's weight, it was slowly slipping.
Friction alone wasn't enough to maintain the rod's depth.
Gudora was a smart man, and hence, the moment he realised the crystal rod was slipping deeper thanks to the excess weight, he let go of the corpse in his hand, watching it cause a loud splatter upon slamming into the floor of the pit, "Vicious bastard! He placed a trap that would shatter upon his death."
What he didn't know was the existence of two Empyrean Zingers. The first was located within the Inala puppet's stomach while the second was located within a dummy Sumatra Zinger.
