Danni babe

Best answer as chosen by Asker / Ratings
What you need to do is Run backwards away from the T-Rex and shoot it as much as possible then when the red meter fills (underneath it's health) it will charge at you then you press the circle button and move your analog stick thing to the left or right to move away when it gets close once done this there should be a red circle around near it's eye. When this red circle appears shoot and it will bang into the wall. Repeat this until it dies.