The act of jumping off a cliff comes with its consequences, as Zhou Tian found out when he lost a million HP upon landing. Although Zhou Tian was beginning to recover health at that point, a glance at his circumstances at the time would reveal that he was still in great danger.
At least, Zhou Tian had not yet fully escaped the influence of the volcanic eruption.
After all, with the volcanic eruption, it wasn't just the volcano itself that posed a threat. Indeed, it could be said that there was hardly a place in the vicinity that could be deemed as safe. If Zhou Tian didn't want to let all his previous efforts go in vain, he would still need to stay away from the erupting volcano.
However, going by the actions of the Elemental Spirits, Zhou Tian knew they wouldn't let him depart so easily. Under normal circumstances, only a handful of Elemental Spirits were strong enough to give Zhou Tian pause, most didn't pose a major threat to him.