Can't find Masterball in Darkrai Cult

I haven’t started a new game and can’t find it in the seed flare + surf area @ Darkrai cult base.

Go to the room where darkrai was summoned. The one with the PCs. Seed flare and swim to the bottom left.

I found it eventually but appreciate the reply.

Do I get it in the cresselia and darkrais event before e4?Then I get it​:sob::sob: