Your only problem in the index is to find enemies to kill fast enough, this build is here to solve this problem and replaces your aura with [Enemy Radar] and your Exilus with [Enemy Sense]. Combined with [Animal Instinct] on a sentinel, this is essentially enough range to see the entire minimap in most index missions if you're standing somewhere in the middle.

Just run to the next enemies, pop your regulator, and move on to the next one.