추공 (Chugong)
The fact that restrictions only apply while he's in the quest area, while time "resisting" the enemies counts no matter where he is seems way too convenient. He could have returned fully restored, better equipped and leveled up and actually fight for a few real hours to get to the same result. He could also return exhausted, hurt and manaless, but calmer, better equipped and way stronger, with a lot of accumulated time and enough strength to barely win. The fact that the plot was so convenient makes his victory feel cheap, unearned.