I found a way to get a relatively consistent double kill with the shotgun on the group of three enemies you need to kill at the end. As soon as you round the corner, you need to aim in the middle of their heads and shoot after you've ran a little bit out from the corner.

This could go 46s if you kill the enemy far down the street with a RNG one-shot kill with the shotgun, which is possible, I've done it before.