if u cant get past that then good luck w/ the rest of the game (my frend beat it on the COMPUTER)

when u first start go over the tree then when u get 2 the other side and get on the plasma
turret and shoot the grunts in the middle of the trees in front of u then get off on turn
right go into the building find where the flood break throuth the doors and then go back
the way u came go out side and follow the soldiers and then you will finish the mission