I think the point is, under the current system, if you're healed for 99% of your HP, you die.
This works in 20% increments, so if you're healed for say 50% of your max HP, or 2 stacks, you only have 3 stacks remaining or 60%, and when the 10s is over, you suddenly lose 60% of your max HP.
This could mean you still survive.
