After the cutscene, you get your pick of a decent selection of weapons. I would recommend picking up the retro lancer. It takes 2-3 shots to take out an infected (yeah, they remind me of L4D) and it comes with 210 rounds. Should last a while. Clear the next open area and through the building to another. Just keep back peddling and then when they are clear, head through the door. The next few areas are actually empty so just follow the path and you'll come to a cutscene.
*cutscene*
In Gears 2, that cutscene would have been downright scary. After the cutscene hold off the attack coming from the church, and then enter it. Grab the lancer then go off to the left side and break through the barricade. Once through the barricade, turn left and climb up (take cover and then mantle) and on the wall will be a collectable. Turn back and go down the ramp and out of the tunnel.
You'll get a quick cutscene and then have to get rid of some locust. As you clear the locust below, you'll be attacked from behind by lambent. Kill what you can of the stalks and pods. Keep fighting and when it starts to get bad you'll get a cutscene
*Epic Cutscene*
