- "Thunder Two-One, I've popped red smoke in the treeline. Stand by to engage on my mark!"
- — Ghost to Thunder Two-One in the level "Loose Ends"
Thunder Two-One appears in the level "Loose Ends", and is called by Ghost to eliminate pursuing Ultranationalists in the treeline. Ironically, it protected Ghost and Roach from the Ultranationalists just long enough for them to be betrayed and killed by Shepherd.
- Rarely, Thunder Two-One can be shot down by an RPG-7.