Pandora is a continous loop.

We all know that there is some kind of 200 year cycle, and it is likely that every 200 years when that vault opens that the destroyer butts his head into the world. It's also likely that your character is just some unlucky sap that is skilled enough and shows up at the right time to make the way through getting the keys and killing the destroyer. LIkely your character was meant to be the one to actually open the vault (hence the "it isn't supposed to be this way" line when the key is stolen.), but even with Steele opening the vault the results are the same. The people involved with the cycle are not the same every time though. Every 200 hundred years there is some hero that kills the destroyer, this game just takes place during this current cycle and the character you pick is that random sap hero. In the next cycle 200 years later, there will be some one else. The rolls of other people will be played by different people also. The cycle is not so much a repeat of time, but of events with a same beginning and end, but the middle is different. Think of it like fate, there is a destined end to it, but the events that lead that way are not the same, but they will always lead that way. Also many of the comments that the TC used as proof could be taken many ways. "I knew you were the one" You just killed a ton of bandits on your own and walked away. She is simply commenting that you have the skilled that would be needed for the guardians end plan for you. The guardians repeated assurances that you will win really could be nothing more then a means to tide over the fear of the challenge that is coming. Encouragement since you are one lone person against many. "No this isn't supposed to happen!" It was obvious that the guardian had meant for your character to open the vault with the keys not Steele. I am betting that line was aimed more at the fact that someone else was going to open it and the destroyer would find a host before your character could get there to kill it. Mayb?