User blog comment:Hyperborean/"The House of Hades" – official expectations blog/@comment-5850470-20121217235414

I wonder if Jason's flaw of caring more about duty than loyalty to his friends could make something like this happen...

Percy tries to sacrifice himself to Tartarus out of loyalty

Frank intervenes because the quest would fail without Percy

Jason sacrifices himself instead because he cares the most about their duty to defeat Gaea (even though his friends would be devastated)

Any other theories?