Some general hints that helped me.
You want to kill the mud mother as soon as you can. If the mud grows 4 tiles wide and fills the hallway you have lost. What's the best strategy for killing the mud mother? Get as close as possible to her. You need to get to the west side of the room with the aumtlich on your east. A combination of stunning and pushing can accomplish this.
Efficiency is obviously important here too. I found that I needed to clear a couple of layers of mud in each spawn cycle. exploding the mud by guiding the aumtlich diagonally from the south east to northwest corner of the hallway with me to it's west was a tactic I used a lot. Then I reset the pattern by going south using vertical preference to keep the aumtlich parallel with me and pushing it back east.
This is somewhat hard to describe, so I've attached a very inefficient demo that hopefully gets the idea across.
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Links to neat forum tools that I always have trouble finding:
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(but I was just luck 
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