Here's some stuff I noticed:
There's nothing wrong with double-knee sliding, but it doesn't do much if you're already protected by the bunker.
Keep your gun up, even if you aren't shooting. That extra second it takes to pull back up could cost you a kill or your life.
When getting shot at, don't worry about your whole body. Your waist should act like an anchor, and always be in the same place. The only things that can get shot are your arms/gun and head, so those should be the only things that require a good amount of movement while in a bunker.
While running to your bunker off the break, watch down the field to see where the other team goes.
Get a better camera man.
Hope that helps!