The 4-sided geometry represents the four paths the players can choose to fully realize their abilities as dimensional travelers.  To reiterate what George had to say- there are really two choices hidden within these four, you can either choose to rely solely upon yourself, or you can accept the guidance and help of another.  You should know that the Guardian, or instinct that you were promised was really a false self representing temptation, following that entity's instruction is akin to choosing to let somebody else do the driving and perhaps heavy lifting over the rest of the campaign.  I had seriously considered what I should do with your characters if you had made such an obvious turn to the dark side.

Choice 1 was always intended to be the starting point for the players.  When they awaken, they are lying upon the floor, at the very locus of the first option.  This option is entitled Endurance, but it could have as easily been labeled persistence.  It represents the choice to perservere along the hardest yet most direct route.  If any player had decided to chance that route, they would have found that it is impossible to fall through the floor and out into their mind space.  It takes supreme mental effort to pass through this portal (think multiple jumps and puzzles through a maze or obstacle course), but it is well within their abilities and requires no outside aid from Tim'met.  This path leads to the Ordered Realm and from there into reality and carries with it a number of subtle advantages relating specifically to cognition and perception.

Choice 2 represents Fortitude or Courage, but it could also be titled self confidence, faith or any number of similar terms.  It is the path of the resolute and represents a willingness to chance things on your own rather than submitting to the will of an external entity.  Much like Endurance, it begins with a leap of faith and leads the player into the Ordered Realm and back into reality.  Taking this path yields an unusual ability that I will leave for you to discover on your own.

Choice 3 is in my opinion the most dangerous option and entails the greatest loss of autonomy.  It is entitled Fervor but we could also label it as zeal, passion or even enthusiasm.  This path leads to the Shadow Realm and from there to reality.  The altar and sacrifice represent a giving of at least a part of oneself to the mission of Tim'met and such devotion by a character is richly rewarded in the form of all manner of powers.  I can't go into detail without spoiling future surprises, but beware of those who have chosen Fervor, they are deadly adversaries.

Choice 4 is the natural choice for unrepentant warriors.  It is entitled Fury, but words like rage, wrath or bloodlust would suffice as adequate definitions.  This path also leads to the Shadow Realm and then to reality and it is every bit as much a path in the service of Tim'met as is Fervor.  The Golum represents Ar'kanto and his mission of ensuring free will for humanity.  The act of destroying it is an ultimate act of shunning Ar'kanto in favor of his brother.  Those who follow this route are the soldiers of Tim'met and are gifted with great powers in exchange for their service.  The players are indirectly familiar with these powers, but beware, the greater the warrior and the stronger their lust for battle, the greater the power.

Given that each of the players chose fortitude, I am sure that you will puzzle out the advantages and disadvantages of your path together over the next four sessions.  All in all, it is not a bad choice and one that I intended to be the most logical for you all.  As I said above, it was a potential conundrum if any of you had gone with fervor or fury.