Only one way out

Feeling adventurous you decide to go for the vent. No one is going to tell you to be normal and go through a door. Not when this vent is sitting there just calling to you. Anyway, it must be some sick psychology experiment where some rich, old guy is betting his brother a dollar to see which door you'll take. Kind of like what happened in the movie "Trading Places". I mean what else could it be?

So up the vent you go. After getting all the way in you notice that there are two paths. The one on the left seems lighter while the one on the right seems darker.