The drill and the bat are both very much patience testing weapons.So, the power drill. I thought the baseball bat was an exercise in frustration, it's literally an after dinner mint in comparison to this.....thing. I've read that it's glitched for KB&M and is fine with a controller, it's one of the last things left to do on Dark Matter (rocket launcher and baseball bat too) but I can't get any double kills, let alone triple etc. I've used tactical expert perk to spam smoke and also shock grenades to stun but no joy WHATSOEVER. I hate it more than the Goblin.
Assume you're trying to get the kills on Stakeout 24/7? Its the only map I found that can give you the kills you need, but you do go massively negative trying. I got the double kills on the drill (using KB&M), running down the centre of the map through the two windows and trying to get a bit of luck find those snipers, lmg, AR players distracted firing down through the staircase lobby. Failing that crouching/lying down down in the bedroom near the door and wait for single players to come running through (the bedroom without the duct to A is where I did a few).
Also I was dumb, I got the first 40 kills using the normal 2 hit kill attack, was trying to figure out why I couldn't do what other players were doing to me with that kill animation that stops you from firing your gun. Found out I could use the power attack for a one hit kill (RMB), obviously you're exposed while the animation is going as you are with take downs, but I found it a lot easier just running into players hitting my RMB and getting those kills.
Not done the triple kills yet though. May leave that till everything else is done as I still got a lot to do.
I was kinda resigned to dying A LOT doing the drill and the bat. Of course there is HC Stakeout and run around like a maniac for a one hit kill with the LMB, but I found that a heck a lot harder.