Primum non nocere is a Latin phrase meaning “first, do no harm.” Treat it as a guideline in red teaming. Always remember that adversary emulation should only be performed to an extent that measures the response of the system without exposing it to significant risks—running ZeroLogon or turning AV completely off would be unadvisable as the system will be rendered either unusable or greatly vulnerable to a real adversary. Only use tools and exploits whose damage and risks are within control (and under the rules of the engagement).