Roblox introduced (now Hyperion), an anti-tamper system. While portable executors can sometimes bypass it for a few hours, Murderers vs Sheriffs has server-side logging. If 10 players report you for flying, a moderator will watch the replay. Script or no script, you get banned.
Wait for the "Attached" notification. Copy the MVS script from your clipboard or load the .lua file. ro flux murderers vs sheriffs script portable