With Grenade Launcher, 3 Grenades, 1 Kill
Tipp: When you kill a enemy with a explosion the slowmo pops up. but the time goes slightly slower than the game speed resulting in a ~0:02 Timesave
I've tested to see if slowmo makes the timer any different and slowmo has a slight disadvantage making the timer run faster with it.
You can disables slow-mo in the options! It helps a ton :)
Yeah I tried that and it helps extremely well, when you're like me who likes to do trickshots while flying though the air. :))