I think this is fully in keeping with his previous plan to tear down Azkaban, possibly at the cost of his own life, to save Hermione. It's just that right now he doesn't yet know what he needs to do to save her. In the previous arc he could be more specific.

Also note that Harry does not see "rip apart the foundations of reality itself" as necessarily a bad thing. He's been planning to do that since the very early chapters anyway. Now he just needs to move his schedule forward a bit.