Plus it didn't help that Brian never signaled back to Gracelyn. And naturally she went past it during the temple run.
So many things went wrong in that run.
First, the frontrunner should not have went into the Ledges after trying only two books. Then he wouldn't have ran into that temple.
Second, he wasted too much time in the Ledges and by the time he reached the Observatory, a minute already pass.
Third, he did not signal the half-pendant to his partner.
Fourth, the secondrunner SHOULD'VE saw the half-pendant as it wasn't that obscure at all.
And finally, both players wasted too much time with deadends and backtracking, so they really had no chance to win.