I was playing the open world stealth game
Metal Gear Solid 5: The Phantom Pain (2015) and I kept failing Mission 33 ("Subsistence: C2W")... The "Subsistence" label means it's a remix of a past mission, but this time you have to complete the mission without any starting loadout, and rely purely on whatever equipment you find after you begin the mission.
The goal of C2W is to destroy some buildings, but "Subsistence" means you don't begin with any explosives -- and once you start attacking the base, they call-in an enemy helicopter that will kill you very quickly. So your two options are (a) sneaking around and clearing out the base quietly so you can destroy the buildings in peace, or (b) finding some heavy weapons (conveniently, some nearby guards carry rocket launchers) and quickly blowing everything up and escaping before the helicopter kills you.
I kept failing with either strategy, so I decided to look up some tips.
The online guide suggested a rather dishonorable trick... (1) destroy the nearby anti-air radar station while in "free roam" mode, outside of the mission; (2) then, finally start the mission, set your own helicopter deploy point
right on top of your mission objective; (3) and basically kill everyone with the helicopter's giant overpowered chain gun, easily earning the top S-Rank rating for your performance.
My (wrong) assumption was that changing the world in "free roam" mode would not change the world in "mission" mode. In most cases, this was still true... except in this one instance, the radar station was leaked between alternate realities.