Amazon says its newly released game-development software shouldn’t be used for “life-critical or safety-critical systems”— except for in the event of a zombie invasion.

The terms of service for Lumberyard, Amazon’s new package for game creators, say that the software isn’t intended for use to operate medical equipment, automated transport systems, aircraft or air traffic control, manned spacecraft, or military use, according to a report by the Wall Street Journal.

All bets are off, however, if the U.S. Centers for Disease Control confirm a “a widespread viral infection transmitted via bites or contact with bodily fluids that causes human corpses to reanimate and seek to consume living human flesh, blood, brain or nerve tissue and is likely to result in the fall of organized civilization.”

Lumberyard was released for free Monday and the game engine is integrated into the Amazon’s cloud services and other platforms. This isn’t the company’s first foray into the zombie apocalypse — their zombie protection store is no joke.

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