Strangelove sets up MSF by disabling ZEKE and the MB defenses, at which point Skull Face and a small unit secure Strangelove and ZEKE. Reinforcements are called and XOF troops begin an area/boat assault on Motherbase. Big Boss arrives seeing the base on fire, believing the package inside Paz to be the only thing XOF had planned for them. Paz attempts to reason with XOF troops, but is shot and presumably killed.
Big Boss fights his way through to rescue Kaz, who he gets back to the helicopter. Kaz tries to talk Big Boss in to retreating, but he says hes not abandoning his soldiers because they wouldnt abandon him, and begins to fight his way through the soldiers with Kaz providing back up fire. Big Boss mistakingly believes that Strangelove is being held by Skull Face, and attempts to rescue her.
She pulls a gun on him, he looks all betrayed, then Skull Face shoots him in the chest and he starts bleeding out as Skull Face boards ZEKE and Strangelove is escorted away by XOF troops. Kaz, Amanda, and a small unit rescue Big Boss, whos now unconscious, and get him back to a helicopter which ZEKE opens fire on. Kaz and Big Boss are caught in the explosion. Chico, who was hiding behind a container, notices Amanda and joins the group.
Amanda tells them to get to another helicopter while she attempts to hold off ZEKE, Kaz and another soldier gets Big Boss in to a helicopter, and they begin flying away. Amanda is still in MB while it goes up in flames.
They arrive on an airship carrier, where Chico goes in to shock and gets taken to the medical wing with BB and Kaz. They attempt to resuscitate Big Boss, hes in a coma, Kaz points them towards Chico whos heartbeat has now slowed and a beeping noise starts inside his chest. The doctors look on in horror as the beeping increases and it cuts to black.
Theres an Ocelot phonecall aswell.