Ever since Lev's consciousness had directly traveled to the future and assumed the identity of another Lev, the timeline of the future had branched into two. The future where the Hive Mind took over the world and the future where the Hive Mind was destroyed... these were the two possibilities of the future when the aberrant that is Lev traveled through timelines.
But another timeline was born when Lev traveled back to the past as the bomber of Trek Industries. Lev had no recollection of ever jumping to the past as a bomber but apparently, it happened. And when his consciousness traveled back to the past, the future him actually wrote a note for him. The note prompted him to do it right this time, and that's why he had to think up another way to change the future.
