Betrayal is the nineteenth mission of Metal Slug: 2nd Mission. Only Red Eye has access of this stage. Three prisoners exist in this stage.
Red Eye takes notice of Col. Tender, a Regular Army member who switched sides, and takes chase on a moving freight train. Whenever Red Eye is outside, she gets pushed back to the left unless an obstacle is in front of her. Throughout the mission, Col. Tender is seen panicking and running away in fear, and once he is cornered, he kneels and begs for forgiveness. Col. Tender is counted by the game as a POW.
|Urgent Message! In alien base… the fugitive Col. Tender has been spotted! Should I pursue?|
|Tender! That traitor! Of course! Chase him down! Terminate him!|
Completing this mission proceeds to Mission 22 (One Fell Stroke).