Despite the Doom Slayer's best efforts, Pierce was able to open up the Well, a very large portal of Hell on the UAC base, so that Hell will be unleashed on Mars forever. Even though the Doom Slayer gets sent to Hell, Hayden created a tether system that allows the Doom Slayer to be teleported out of Hell at anytime. Hayden tells the Doom Slayer that there is only one way to shut down the Well, go back to Hell to get a key called the Crucible.