To survive Deluge, you need to make sure you're completely immersed and swimming, not just standing in the shallow water. Also, I think someone else exploding on land can kill you in the water if you're in range.
On the siren, you can slot the Slippery CP from the red Fitness tree to break free automatically and at no cost every 21 seconds.
EDIT: Added comment about Deluge
Someone else with the mechanic wasn't swimming and killed you. Ping also plays a part, so make sure you get in the water like 1.5 seconds before it actually goes off. I like to roll dodge in to make sure I actually get into the swimming animation, but that's not necessary.AnduinTryggva wrote: »1. Deluge: When it comes I go into the outer water until I do swim and that's what I do: I swim. As soon as the wave is over I hastily swim back and jump out of the water. On several occasions however the explosion killed me while in water. And no it was not the slaughter fish. I exploded every time during the deluge wave during the cases when I died playing the mechanics.
You may have to spam the break-free button if you're sure you have enough stamina for it; your stamina bar will glow and the low-resources audio will play any time you attempt it without enough stamina. The Slippery CP Star is extremely useful on this fight; I also recommend Expert Evasion as well.AnduinTryggva wrote: »2. Sometimes breaking free from siren's lure does not trigger. Some of these cases might be when I was low on stamina but on at least one occastion I should have had enough stamina for breaking free because I used a tri stat potion.