You decide you should just keep on reading. You think about the state of your bladder and it isn't calling for any urgent action, so you should be good for quite awhile.
But before you press the next button you stop to think about something else. This image. You see yourself. Huh, guess you are astral projecting, albeit with the help of the machine. You can't focus on anything else though, not to mention try and get your eyes back.
Maybe that's why there is no back button. If it's not a part of the story, why would it be there. The more you stare at your own image the more your head hurts. Oh well, let's keep on reading then.