Explain what little Jim would have to do to escape in The Adventures of Huckleberry Finn?

To create as fantastical a story and game as possible, Tom tries to determine how to make Jim into a real prisoner before his daring escape. He decides that he and Huck will have to saw off the leg of Jim's bed in order to free the chain, send him a knotted ladder made of sheets, give him a shirt to keep a journal on, and get him some tin plates to write messages on and throw out the window. To top it off, Tom tells Huck that they will use case-knives to dig Jim out, rather than the much quicker and more appropriate picks and shovels. Tom is kind of like a gruesome MacGyver. I always thought this showed Tom's concern with fantastical adventure over Jim's welfare.