See photo, then read.

But you know the injection would have turned him into the Evil McCoy, and it would have taken Spock and Kirk the entire hour to get him back to normal. 

End scene:

McCoy lying on bed in Sickbay. Kirk and Spock standing by his side.

Nurse Chappel: "His vital signs are recovering."

McCoy stirs, opens his eyes. 

Kirk: "You gave us quite a scare, Bones. Spock has to resort to some very drastic measures."

McCoy looks at Spock. "I hope you didn't inject me with your damn Vulcan blood!"

Kirk and Spock exchange glances, and both smile. 

Yeah, he's back to normal.

Music up. Fade out.