Here's one way:
1. Give the character a boolean variable: isIdle
2. Add your idle animations: "breathing", "looking", "twitching" to the character. Make sure they're not set to loop.
3. When your character is on the ground and not moving set isIdle to true.
4.Add an event with these conditions and action:
Condition: Character isIdle
Condition: Character Compare Frame is equal to Character.AnimationFrameCount-1,
Action: Set Animation to choose("breathing", "looking", twitching) from beginning.
Remember to switch isIdle to false when the character starts moving or is off the ground.