At the end of Virtious Mission, Hold R1 in the cutscene after Snake has healed himself. You will be able to look around when it is not indicated that you can and you can see The Sorrow's body. After you've climbed the mountain, hold R1 during the cutscene where Snake is spying on Volgin on the base. You can see The Boss ride off on her horse and EVA do the "handgesture". After being tortured, hold R1 as Ocelot leaves the room. The Boss does the "handgesture". After defeating the Shagohod, hold R1 and when EVA goes to hug Snake you can see The Sorrow behind her. After defeating The Boss, when her horse walks up, hold R1. You can see the ghosts of The Boss and The Sorrow. When the President goes to shake Snake's hand, hold R1 and look to the left. Ocelot is outside the window. When Snake is at the graveyard, hold R1. His eye tears up and you can't see much.