For one, the antagonist seems to infiltrate the compound while pretending to be part of XOF, with a fake helicopter and fake sticker badges.
As for chico, he says to the kid to say hi to "your boss", gives him the tape then says the Trojan horse has been planted... He also talks about a girl that was killed that was supposed to mean something to Chico ... Paz or maybe Amanda ???
To me this kinda hints that the antagonist actually knows and expects Big Boss to show up to grab the POWs , hinting that Chico might be either a double agent, the key to some more subtle plan. Maybe the tape recorder's the real trojan horse too... Allowing the antagonist to pinpoint MSF's location or something.
The two FOX comment seems to hint at FOX and XOF being opposites, perhaps Zero was dissapointed that Big Boss didn't stick with him to lead FOX, so he created XOF. But in that case, who is the antagonist working for and why is he gaining access to a XOF base with fake clearance gear.
I never quite understood the FOX logo on Big Boss's attire in Peace Walker. I mean, FOX was the old unit in MGS3 and Big Boss should have no ties to them anymore. Didn't he also recieve a letter hinting at the creation of Fox-Hound at the end of Portable OPS.
In any case, at one point in time ,Big Boss will have to gain control of Foxhound... And since Foxhound is at least partially controlled by the US, it means either Big Boss manages to play Zero real good and be a double agent... --- The wind carried screams from the west. I could not help but smile - Kain PSN/MGO ID : Stealth_Cobra | MGO Character : Stealth_Viper