You're in the FlubCo Scrub Pens, and in each of those sectioned-off areas there should be a Mudokon or two to rescue, right? Well, if that's the case, then right up at the top you need to find a lever and pull it. This lever opens a door.
Now, if you go back to Munch, you can take him through the door and into the area with lots of explosives, but be careful not to put him in the water just yet.
Now, back with Abe, try and find a lever marked 'water release' or something, I forget the exact phrase, but you should understand it. It's guarded by a Slig, so you might want to create a possession orb and take him out before you go down. When you flood the sectioned-off areas, you are making it possible for Munch to swim to where Abe is.
While doing so, you should be able to use Munch to pull another lever on a little platform. This opens another door, the one next to the 'water release' lever. Don't make Abe go through yet, he'll be shot dead in seconds! Instead take Munch to where Abe is, by the door.
Look all around you for a Zap Vendo. Make Munch have a drink, then go through the passage that's next to the vendo to find three Sligs that desperately need killing. Once you're rid of them, you're free to leave the sectioned-off area behind, and can even enjoy the benefits of a Health-Up (or SoBe if you're playing the American version).
That should help you out, assuming I understood you correctly.
Good luck!
Munchs Oddysee...I need Help
