Plot hole: It's never explained why Batman would interrupt the procedure that could've saved Clayface's life.
Suggested correction: A plot hole is when there is a logical inconsistency that benefits a story despite not making any sense. Something not being explained is not a plot hole. And the reason Batman interrupts the procedure is because Clayface is a criminal who has committed numerous robberies as of late, and Batman is there to apprehend him. As far as Batman is concerned, if Clayface wants to undergo the procedure, then he must do it while in custody.