Incredibly difficult, would be easier if the arrow minigame was in sync with the swimming and perhaps finding a way to put the UI closer together so it's possible to keep track of your position while doing the arrows maybe?
Potentially some kind of communication device on Hydna that relays arrows to them (maybe making it closer to a quick time event so that it's easier if you look at the other screen but it's possible to manage talking and swimming at the same time)