the fact you have a kit makes it give you a +1 to the dice roll
I dont see any indication of this ...
It says x1 not +1
And on time 0:33, when bonuses are counted, you can easily see there is nothing that disarming kit adds ... it only shows there so you know how many of them you have ... and it counts as x1 so it dont affect results i would say.
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I still think that no matter if kits should, or should not (or rather are, or are not since i really doubt Larian would tell us their desing desires out of sudden) be consumed on use ...
There is imho still quite important question if there even should be option to disarming allready activated trap ... i mean, im no engineer, so honestly i cant really imagine how would statue in the wall that after triggering will hurl firebolts in regular intervals for eternity would even work ...
But from basic DnD stand point i feel like once trap is triggered, it should be too late for you. No?