I have this funny theory that anyone who fuses with an alien have the ability to sprout drills regardless of which alien they fuse with. But while somebody who fuses with the Drill clan can only sprout drills, somebody else who fuses with the Yellow Knife clan can also produce sonic waves. Of course, this is a disadvantage for the Drill clan but the reason I thought up this theory is because you can only become a part of one clan and the only way for other clans to sprout drills is if they can do it from the start.

Either that, or the Yellow Knife has an ability to insert its traits to a Borg.