In Editor:
1. place player and playable rifleman near the ocean
2. place an MH-9 hummingbird with almost no fuel nearby
3. start the game
4. switch into the rifleman
5. board the helicopter and fly low over the ocean
6. team switch back to the player on land
7. helicopter runs out of fuel and crashes into the ocean, but the AI doesn't get out and drowns
8. team switch into the drown rifleman
At this point you are stuck in his body, but cannot exit the game or return to the editor.