×The approach you are using won't get you through in under 31 moves (I'm actually surprised that it even works in 31).

×Considering that, you will have to find a solution that does work. Let's look at the contents of the room that could possibly help you: There's a mimic, but if you send him through the area you won't be able kill that last tar baby.
That's not to say that there is nothing else that can help you:

×I assume that the mimic has to be near the disarm token and there should be some tar to restrict the mimics mobility.

×you'll have to drop the trapdoor at 17,5 so no one blob of tar alone will allow the tar to fill the passageway. This means you'll need to have two pieces of tar at 14,6 and 17,6. Considering this, you'll need to somehow keep tar alive while moving the mimic and yourself to get rid of it once finished.

×For the east it's very hard to get the tar out the the corridor from that side, but the west is also hard to destroy without placing a mimic in one of the chambers. One of these is actually impossible the

×The west is simpler, sort of, if done correctly, so I'll help with the eastern side: Clearly, the only way to get the blob out is to let it grow over the trapdoor, but it blocks your path unless you step over it. Since this drops the trapdoor, it prevents the tar, so you would seem to be stuck but

×What I mean is that you know that it would seem impossible to be able to get around the tar blob in the eastern corridor since you can't do so without using the trapdoor, but stepping across the trapdoor prevents you from getting past the tar. Of course, something in the room provides a solution to this issue.

×The delver needs tar on (14,6) for it to grow into the central corridor. But once there is a tar blob on (14,6), it is uncuttable from the outside. So perhaps the delver himself must go into the western section, and destroy the tar from the inside, once it has done its job and trapped the mimic where it's supposed to go? But that's also impossible, because by that time there must be a blob at (17,6) as well, and that, too, is uncuttable. So by that time the delver must already be on his way down to the southern section. But that means that there is uncuttable tar in the room, so the delver is trapped by the black door. Hence, the room is clearly impossible!

×A tar blob at (17,6) isn't uncuttable - it's just uncuttable from the north.

×get through the bottom section and strike the orb within one growth cycle, and still conquer the room.