It was brought up in the "How would you do TOS differently?" thread that a number of episodes end with horror, only to be succeeded by a scene with crazily inappropriate, if humorous dialogue and behavior.
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So they beam Redjac's innocent and incapacitated host, out into space, where presumably his corpse will drift forever, containing Redjac in a physical form from which he cannot quantum leap, or whatever it is he does.
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What are your most mind-assaultingly inappropriate endings to otherwise serious episodes?
I think they DID establish that the body was dead and that Redjac was only animating it, but I take your point. While I enjoy the humorous interplay between the main characters, there are times when it was misplaced, and this episode definately was one.
"The Changeling" is another one, although not as big an offender. They don't break out in guffaws at the end, but Kirk does joke about Nomad...after the epsiode established that Nomad extinguished an entire populated star system, if I remember correctly.
You're right; sometimes it would have been better for a more reflective coda, as seen in "Where No Man Has Gone Before" and "The Man Trap."
Ive just watched The Changeling over lunch on my day off. Its surprisng, the humour is, well, not in your face but its acted with a sincerity somwhat to the events. About Kirk, Spock and McCoy being the 'parents' of Nomad somewhat.
But in hindsight, Nomad had killed four security officers, killed Scotty and repaired the unit, the three or four officers in engineering (Dead or stunned you decide) wiped Uhuras "Knowledge" (Not entire memories as some fans seem to still think. She speaks Swahili still in sickbay with Christine, so its predominantly her knowledge) which is also baffling as by the end of the episode shes at college level already

and the fact she was not sent to a specialist Starfleet/Federation rehabilitation unit somewhere for professional and supported re-education and instead stayed onboard the Enterprise for the next few years.