I said on my previous attempt I thought there was a better route. I found one.

Most enemies on this mission will deal more HP damage than armor. Enemies are also frequent enough that keeping armor topped off is pretty consistent. This allows the faster reload speed equipment over starting with armor to be viable. It is also faster because ammo is tight until the basement is finished, and without the faster reload it's easy to be stuck waiting.

Breach charges may seem like they would be faster because of saving the Killing Spree buff to 1 shot multiple enemies in a room. The trouble with that approach is the green vest, gray vest, black ski mask, machine gunner, and green shirt enemies can all get a shot off the same time you do. All of those enemies deal HP damage even with armor on. With 75 baddies to take out, this can wear you down very quickly. Stopping to drop an HP pack can easily waste 3 seconds and losing all the time potentially saved by using breach charges over smoke. 4 smoke is also just enough to cover the major threat rooms, where you'd end up short 2 breach charges (one of the rooms smoke is used requires 2 breach charges to maintain Killing Spree).