Gunslinger Guide
Step #1 – Pick up the “Dynalar Sandevestan” cyberware. The reason for this is because it slows down the time while holding down L1 + R1 or LB + RB. This makes the grenades easier to hit while in mid-air.
Step #2 – Next, you want to Start the Police chase and then shoot one of their grenades while it is in mid-air. Easier said than done. You must use a revolver, either one dropped by various enemies throughout the game, or one you purchased at a shop.
Make sure that you shoot the grenade while it’s in flight as opposed to once it has hit the ground.