What happens when a player kills the controller's only unit at a Contested Battlefield during staged Combat (while the controller still has a Hidden card there), and when can the Hidden card be played?

Ruling: This is currently a hole in the rules. When the unit is killed, Combat stops being staged (since units from two opposing players are no longer present), but the Contested status remains with no mechanism to remove it. The battlefield becomes stuck in a state where it's controlled by one player, contested by another, but neither a Showdown nor Combat can be staged.

Sequence:

• Player A moves unit to Player B's controlled battlefield, applying Contested and staging Combat
• Player A kills Player B's only unit (Poro) via Shakedown during the trigger reaction
• During cleanup, Combat stops being staged (no units from two opposing players present)
• Contested status remains but cannot be removed (only removed during Showdowns/Combats)
• No Showdown stages (battlefield is controlled, not uncontrolled)
• No Combat stages (only one player has units present)
• Battlefield becomes stuck: controlled by B, contested by A, with no staged event

Nuances:

• The Hidden card cannot be played because there's no mechanism to progress the game state
• A future rules update should remove Contested status when Combat stops being staged due to lack of opposing units
• If Contested were removed and no units present, battlefield would become uncontrolled
• If Contested were removed with units present, a new Showdown/Combat would stage