seems like yor moving slow, in 2.0 when i would spam that for myth would have that group dead b4 tonberry got there, then would pull everything after to door, kill the one tonberry and have my smn friend swiftcast bind everything and engage boss so eneimies got stuck behind purple field (blm can sleepga too)

otherwise u can pull the whole group right to the corner, then after ton passes can pull the group in hallway in the corner on same wall as trap chest without triggering it
ton will go left around the trap chest then down the hall to the boss and back, then left and leave the trap chest room