So you start of every encounter by switching from you secondary to your primary and activating a booster shot. This increases your DPS to around 600K - 700K. Why such high dps you ask? Well, you get damage bonuses for your smg's on the pred and alpha talents. Buff that with the booster, plus the buff from the Barret's vest.. boom! Enough said.
When you run out of bullets on your primary, also assuming you've lost a bar or two on your health, switch to you secondary while deploying your immunizer. This will activate the 2nd buff (10% armor) from the Barret's vest.
When you drop agents, finish them off with your shotty to proc predatory and get the health regen. Note, you also get 100% health regen from the alpha talent, so what more could you ask for?