Instructions
Equip the syringe and use it on yourself.
Use a long-range weapon and shoot the doll that hangs from Screaming Mantis' right hand. After two hits, a cut scene will play.
Shoot Meryl with tranquilizer darts when she comes after you. When she is sedated, continue to shoot the doll on Screaming Mantis' right. When the doll has been shot twice, another cut scene plays.
Equip a tranquilizer weapon, such as the Mosin Nagant, and shoot Meryl until she is knocked out. Repeat this process each time she holds the gun to her head.
Continue to shoot the doll on the right side of Screaming Mantis until it falls off. Pick up the fallen doll up and equip it in your weapon slot. Use night vision to help find the doll.
Hold down "L1" and aim the doll at Screaming Mantis. Press "Fire" and, with "L1" still held down, shake the PlayStation 3 controller.
Move backwards as Screaming Mantis' beauty form walks towards you and shoot her with your Mk. 2 pistol. Press "Triangle" when she grabs you and then shoot her in the head when she is on the floor.