Things You'll Need
Instructions
Equip your M4 outside of the Mantis chamber. Make sure you have plenty of ammo and a scope. Syringe yourself before you enter the chamber.
Run up the stairs and into the circular room. Mantis will appear with two floating dolls next to her. These dolls give her the power to control the living and reanimate the dead, and they will be your primary targets during the battle. If you had not syringed yourself before encountering Mantis, she would have used the dolls to take control of your body. Target the dolls with your M4 and, after centering on them with the scope, shoot them.
Avoid Mantis as she dives at you. She will dive at you after you successfully deal her dolls enough damage. Continue to fire at her dolls until Mantis takes control of Meryl's body and makes her shoot at you. Run towards her and syringe her to lift Mantis' control.
Shoot down the soldiers that Mantis reanimates and uses as weapons while continuing to target the dolls with the M4. Mantis will again take control of Meryl during a short cut-scene and attempt to make her shoot herself. Syringe her again to lift control.
Fire at the dolls until Mantis drops one of them. Immediately run over to the doll and pick it up. Refocus your efforts on the other doll until Mantis drops it, and pick this one up as well. Equip the Psycho Mantis doll and target Mantis. Mantis will be completely under your control. Hold down L1 and shake the controller. Mantis will flail around and hit the scenery until her health is reduced to zero. Her death ends the battle.