The Hydra is a very tough enemy to put down. It wasn't meant to be killed by the challengers but it has been weakened so that they will have a fighting chance against it. He may have failed numerous times but he has learned not to hope to kill the creature.
Now he knows why the heads must be cut off, because only then will he have enough time to do something other than watch the hydra regenerate. This entire experience reminded Soverick of the difficulty of killing him in his past life. It didn't help that crushing his head won't stop his regeneration at all. Only debilitating destruction could kill him, but he doesn't have that kind of firepower to overwhelm the Hydra's regeneration.
"This isn't working." He complained in the safe zone after another 10 runs of failure.
He always sits and reviews his performance after each run. He would change his plan after all variations of an attempt has failed.