User:SOTO/Forum Archive/The Panopticon/@comment-4028641-20151008023030/@comment-30325516-20191107210811

"While the Doctor was battling depression, his greatest enemy, the Master, was teetering on the verge of madness. His descent into savagery on the Cheetah planet after his last encounter with the Doctor had tipped the balance of a mind always prone to paranoia over into uncontrollable obsession. Having now regained enough control to make his escape, the Master was determined to destroy the Doctor once and for all, even if it meant he had to die in the process."

This is an extract from the scene where the Master swallows the Deathworm Morphant. He then travels to Skaro and goads the Daleks into putting him on Trial.