Never been able to figure that out myself. Some animations you can only see outside the gallery. That one above is one them. Other ones would include the second animation of the pink-hair researcher getting violated by the researchers, the girl violated by a researcher on a bed, and etc. Some animations that should be included in the gallery, but don't seem to work, can also only be found outside the gallery. For instance, I've never been able to see animation of Ex-Ill with the enemy that grips the prison bar unless it was outside the gallery.