How do I escape Purple Tentacle's shrink ray?

Hint 1 of 7:

No matter what you do, Purple is going to shrink you somewhere, somehow.
The best that you can manage is finding something to do once you're shrunk.

Hint 2 of 7:

There is a passageway that is meant only for small creatures.

Hint 3 of 7:

And it connects two rooms.

Hint 4 of 7:

Try to open the door in the middle room of the second floor (the one where
the depressed novelty salesman was staying).  Do not walk to the door first
-- just open it immediately, and you should be able to go inside.

Hint 5 of 7:

Notice that mouse hole?  Crawl through it while you're still small.

Hint 6 of 7:

Now it's time to find a weapon in Green Tentacle's room.

Hint 7 of 7:

The bowling ball might work.