As far as I can tell what you want can't happen currently. In terms of code, Construct (or any engine) checks things 1 at a time. This means that in every tick the game will first check if bullet A has hit it, and then bullet B. Since you destroy the object immediately on either event, both variables cannot become true because the object is destroyed before this becomes possible.
My solution would be to have a small timer.
Give the enemies an instance variable called "deathTimer". Make its default value 50 (or something).
if Drones - HitA = false
OR if Drones - HitB = false
Subtract 1 from deathTimer
if deathTimer = 0, destroy Drones
This will give you "deathTimer" amount of ticks for the enemy to be hit before being destroyed. You can experiment with the number of time to give so it suits you.
I hope I understood your problem correctly and that this was useful.