Audio problem: April's walkman keeps playing for a while spreading in the air the suave notes of The Barrio Boyzz's "Conga" even when the batteries already came out on the first strike. (00:15:40)
Audio problem: Battling the Norinaga soldiers in the castle, Donatello parries several katana strokes using his wooden bo, which causes sharp metallic sounds every time. (00:22:50)
Audio problem: April is lowering the cage where a random doppelganger of Elias Koteas appeared in Feudal Japan. She says "I know I am gonna regret this", but her lips are not moving. A moment later she shouts "Well, come on!" and again there's no articulation of sounds from her mouth. (00:33:00)
Audio problem: Raph quotes Terminator just before he jumps in the waste disposal chute, but the animatronic's lips don't move. (00:34:00)
Audio problem: Michelangelo runs inside the burning hut yelling "Here I go!" with his mouth closed. (00:46:10)
Audio problem: When Leonardo stops Daimyo, the words "Hold it, Bucko" are heard, but Leonardo is not seen to be speaking at all. (01:15:30)
Audio problem: When Walker confronts the Turtles in the Daimyo's courtyard, he says "My God, who's your tailor?" One of the Turtles says "We're naked." but none of the Turtles' mouths move. (01:17:45)
Audio problem: The Turtles reach Walker's chambers. Seeing that he's escaping, one of them yells "C'mon, Mikey!" but nobody's lips are moving. (01:20:50)
Answer: Michelangelo wants to stay behind for the same reasons as Raphael: because in that time and place, they are well respected, even revered as heroes. They can live openly and not be banished to sewers or subway stations.
LorgSkyegon
Mikey didn't want to stay behind because of Yoshi but because of Mitsu. Raphael even points out that she's the reason he doesn't want to return. When Mikey says they should stay, Raph responds, "Now, forget about Mitsu and give me the scepter."