it does take some practice to get used to T5 as healers, especially for the second set of dive bomb when there are 8 people and 3 snakes on top of each other, it is hard to see the dive bomb symbol, with that being said, if you focus target twin at the beginning of the fight, whenever the twin is coming back down to do the dive bomb, you will see its HP bar reappear, that is the cue for you to move.

i placed focus target bar right next to both tanks HP bar so i can see them all at the same time.