The Transformation has a time limit

"Well, he should be perfectly safe, at least for the next 120 hours." Walter replied shyly.
"120 hours? That is 5 days, what happens after that?" Klaus wanted to know.
"The 120 hours is the amount of time that the pocket dimension your original body was moved into will stay stable and accessible. If you do not change back after that time, well..." Walter began.
"Well, then what?" Klaus followed up.