After Jones leaves Kollos' quarters, there's a cut to a reaction shot of Kirk with his hair parted in reverse.
At the end of the dinner, Kirk finishes off his glass, then the camera cuts to McCoy. Then it cuts back to Kirk and his glass is full.
Kirk aims his phaser at a berserk Spock's head and fires, but the beam hits him in the stomach.
It is established that during transport of Ambassador Kolos, the protective visor must be worn to prevent insanity. In the final scene, when Spock transports the Ambassador off the ship, he wears his visor. But Kirk remains in the transporter room and witnesses transport without a visor.