Trinity does not use my Bottomless Potion of Mutilation?

[esdchan]

I drop all the way to 0 HP and it still does not use it...?

 

[野獣先輩]

Did you drag it down to the skill bar? Pretty sure it will use the one there. Which can be disabled if you just changed potion.
Default setting is to use it only at 35% or below. If you got oneshotted at 36% it had no time to use it.
Otherwise post logs.