It also wouldn't make sense for it to be your reflection, because of where you're standing & because of that door or bit of wall or whatever the hell it is that the other face seems to be behind. That's what gets me.
...i was actually going to ask, "Do you mean the person sitting down back there?" but i think i'm just matrixing. Like, seeing disparate things & putting them together so they makes sense to my brain, like seeing faces in floral fabrics.