The team members looked at Ye Yan attacking the Gigantic Wicked Turtle as a superhero, but Ye Yan is not Thor and the cheap hammer he is using is a wood quality item, not the divine weapon Mjolnir.
Ye Yan attacked the boss and soon after, taking advantage of the boss's moves, he got away from it.
After seeing Ye Yan's moves, the other physical classes started using similar methods to deal damage to the boss.
Soon, the boss died and his body started to fall to the underwater cave floor. The battle was hard because they have still to get used to this kind of battle and the boss is too strong in the water. If they were fighting it on Hell Mode, the team wouldn't stand even two minutes against the boss.
They were fighting on Normal Mode this time, thus it was hard to defeat the boss but not impossible.