S3E7 Ending: Why Didn't Mark Just Lie?

Wouldn't Mark lying to Conquest that all of the destruction on Earth from the Invincible War was his doing (which is kinda true lol) and proof of him preparing Earth for Viltrum to satisfy Conquest's anger?

I thought that's what he was about to do after he said "this is all my fault". And doing so would've probably bought him and the rest of Earth some time to rebuild atleast just a LIL bit. And Mark and Cecil already had it established no one on that planet was prepared to handle any type of conflict in that moment.

I just feel like Mark had literally the perfect tee up to lie to Conquest and stall but then chose to be kind of selfish and reckless. like he should DAMN well know he can't beat the average Viltrumite by now. especially not without massive amounts of collateral death and damage (as has been the theme of the entire season almost)

(also ik the basic answer is just to have some fun conflict for the story, which im happy with >:). but was curious if this came to anyone elses mind or if there was good reason for why he'd choose to deal with it that way)