This isn't a lockout as this does not require a boss force field wall thingy to close off pursuing enemies.
It can be done anywhere in the dungeon.
All it requires is some room to run and a blm or a whm.
Really easy to master but has very little room for error as u only have 2 chances as the timer for sleep will be too short by the 3rd time it is cast.
But anyways, AoE abilities r pretty helpful as of the reason y they nerfed Holy.