Yeah. A lot of people were guessing that Lara didn't know that it was leading to a catastrophe until after she started, which then caused her to maybe go back in time and blow up the mansion to stop her past self from pursuing the journey (which would then basically erase the game we just played, meaning it would have never actually happened).
IDK, but, I'm betting that when we find out it'll be something completely different from that Lol. (I love these smilies, there's one for every emotion!)