in the room as soon as the berserker breaks through the wall...you run forward and on the right hand side just before the berserker...there is a door leading into another room. you run into the room and stand right infront of the door down the hall way and throw a granade at the door and make sure the granade is right infornt of the door so that it will open. (note: it worked for me to use the grande but if that doesnt work, you stand infront of the door and wait for the berserker to run at you. just as the berserker is about to hit you, dive out of the way and he will break the door. i highly recommend the granade) run through the door, it will lead you into another room. you will have to repeat this step about 3 to 4 times and when you get outside in the yard...you switch your gun to the hammer of dawn and use it on the berserker about 3 times. thats what you do.

just make him brake all the doors!