Even though the revelation was unbelievable, everything made sense. With how there were a few changes in the world's dynamics, Rudy was convinced. After all, in the previous world lines, Erika had confessed her love to Rudy, but Rudy at that time, wasn't looking for a relationship.
Ever since the apocalypse had begun, everything had stopped and the only thing the world focused on was to get strong and survive on their own. Everyone could become a hero and instead of relying on others, they could save their own asses.
'Erika went abroad to continue her advanced studies, and she confessed her love to me before leaving… That is how it always went, but this time it's different. Maybe because of the apocalypse, Erika couldn't go abroad? She is as strong as Eric, even stronger in some rankings.