How do you beat final level dead space 2

When you get to the part where Tieddman shoots you proceed as normal where you press the action button to get the spike out of you. Once you finish that part you will be teleported to your brain. Shoot Nicole a few times and destroy the minions she sends after you as well. When that big yellow thing comes up shoot it as much as possible (fully upgraded damage on Pulse Rifle works best). Be sure to not go near Nicole or you will die and have to start over. You can also use stasis on her to slow her down and doing this will keep her from being able to kill you.