First, always creep whilst aiming a weapon (or a brick/bottle) so you are creeping at super slow speed.Creep along the right hand wall on the path ignoring the bloaters and clickers on the other side of all the decrepit vehicles. You'll come to a static runner blocking the path (stood behind an RV), stealth up to him and choke him out. Carry on along this right hand path up to where you path is blocked by debris (a lorry cab), wait for the clicker lurking here to be an appropriate distance away and then skirt this debris sticking as far to the right hand wall as you can.You'll come up to a pathway skirting some water logged ground and there is a door way here. Creep in the door way and take out the first (of three) static infected here silently. You can creep up to and choke them all but if you have arrows you can also use these as long as you one shot head shot them all.Turn left down a passageway (after the first now dead infected) and you come back out into the main section. You can go back into the room at the end of passageway past the clickers you didn't kill through a door a little further up on the right (up some little steps) but it's not necessary unless you need supplies and there isn't much in here. Onmce back in the main tunnel, ahead of you are some clickers and a bloater. Watch the path of clickers briefly until you roughly know their timing then strike out into the water and directly across the open space heading for the pathway opposite. Once you get to this pathway all the wandering clickers are to your right as is the bloater and the only thing directly in your way is a stationary clicker stood on the pathway ahead of you.Follow the path until you are just before the clicker then drop of the path and creep diagonally back across to the other wall. Follow this wall to the truck and boost Ellie aboard. Done.This video does roughly the same though he uses some bricks/bottles at the end to distract the clickers and bloaters that I don't think you need as it makes their paths less predictable.