Will Time of Need save me?

So question on how time of need works. It stats that it reduces damage when below 50% health. Now i’m assuming that this means below 50% health when “hit” by something.

So as an example, lets say i have 100,000 health max and i’m at max health. I stand in an explosion which will do exactly 100,000 damage… If I have time of need, will this explosion kill me? I can see it going either way.

1 - The first 50,000 damage is normal, the 2nd 50,000 damage is less because at that point my health is below 50% and time of need kick in.

2 - Time of need does nothing because when the explosion went off, i was at 100% health and time of need doesn’t apply. So I die in this test case.

Ultimately, the heal build i’m doing is mostly vulnerable to 1 shot kills. I generate so much healing that any kind of DoT isn’t really a threat. So i’m trying to figure out what’s best for preventing people from being one shot. If it works like #2 then I think 20% more health would be better than time of need for my build. Bigger pool of health = less likely to be 1 shot.