Gears of War 2 - If you shoot them, they will stop spewing green acid. When they stop, you will have enough time to run by them. If you are low on ammo, take the path to the right. There is some ammo there. Then come back and start down the main path.

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If you shoot them, they will stop spewing green acid.  When they stop, you will have enough time to run by them.  
If you are low on ammo, take the path to the right.  There is some ammo there.  Then come back and start down the main path.