CQB follows the principle of Silence, violence, silence.
You try to keep signature to a minimum, then, if a firefight unfolds, you go full Indra's Vajra on their ass, then go silent again as long as you can maintain it and sheepishly act as if no one heard you, even if they did.
Sentry neutralization is of course a big part, but so is elimination of hostiles when you enter a room.
The point man carrying the suppressed SMG (and the MP5SD is Hollywood quiet) can neutralize a target in a room before the entire team floods in, and extend the duration of their stealth just a wee bit longer, preventing stuff like their teammates discharging their loud, unsuppressed weapons and sleeping tangos waking up, some turd popping up through a door way which wasn't secured yada yada.
I'm being overly boastful here because I absolutely LOVE their methodology. Makes a LOT of sense.
If they don't encounter a larger force in any room, they could run through the entire compound without ever being heard.
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