Why did Aegon leave King’s Landing?

This is fairly obvious, except for the fact that him leaving King’s Landing could be considered an abdication of the throne. However, since Aemond (Ewan Mitchell) is already the de factor leader of the realm, and his ire is clearly worsening, Larys (Matthew Needham) rightfully suggests that Aegon (Tom Glynn-Carney) get the hell out of there before his brother comes back and tries to finish the job (read: kill him). Aegon will play a major role in the coming events, trust me.