I think that Flik would have traveled back in time.
It may not seem like the most reasonable thing to do, but if he had rescued her, then let Tir lead the Liberation Army.
Though that doesn't sound like neither an option nor a possibility, if I was Flik, I would have gone back in time to save my True Love!
She is without doubt worth it
, I mean, come on! A chance to change the biggest tragedy in your life, to be with the one you love the most... Ahhh... <3