The third level to the sixth level was cleared in no time. After all, it looks like each floor higher we go, the number of portals decreases by half. The sixth floor only had two portals, for example.
Oh, and by the way, the trials got harder the higher the floor was.
On the fourth floor, the elders had to challenge it in pairs. They decided so not only because of the trial's difficulty but also in anticipation of demons appearing again and interrupting them.
As they expected, eight to twelve demons popped as soon as the Elemental Guardian appeared to give them the Elemental Essence. If they were alone, then they'd definitely be unable to handle it all while protecting the guardian.
For the fifth floor, they went with three members per team. Despite that, each trial took them an hour to complete. The number of beyond-god-level demons that attacked them also doubled, almost reaching the point of being unmanageable.