Hand-to-Hand Combat
Just punching other players instead of switching to a secondary. For example:

• Punching an arm or hand to disarm someone for a short period of time.
• Choking out someone that way they have to resort to hand-to-hand combat or switching to a secondary to shoot the choker. And it is another way to use the recon's breathing mechanic
• Punching someone in the stomach to wind someone, slowing them down and the breathing mechanic.
• Haymaker punches to stun or even one-shot.