Enable Developer Console from keyboard options. In case you can't access it using “~”, read the text at the end of this guide.
Start
Hard Rain 3: Mill Escape on Expert. Once it’s loaded, open the console and kick two bots typing “kick” and then the name of the character, e.g.
kick coach
After that, shoot the remaining survivor with a shotgun (one well-placed shot should do it) and use your pistol to lower their life bar, but
don't kill them or the counter won't go up.
Pick the defibrillator from the shelf and use it.
Quit the campaign and repeat the process until you unlock the achievement.
*** Spoiler - click to reveal ***Close the game, right-click it from your library and choose “Properties”, type “-console”, run the game and type “bind "key_you_want" "toggleconsole"” to change the key that enables the console, e.g.
bind "0" "toggleconsole"