Richard didn't take much time to leave since staying there was like sitting on a time bomb. Although he was strong, much stronger than when he returned to this world, he still could not win against tens of apostles who were easily S-rank.
Not to talk about there being an anomaly among the apostles who can summon a dragon.
That's why Richard escaped the mansion and returned to the academy—this time using teleportation to reach the nearest town of the academy. Considering he used the teleportation centre of the academy to come here, he had to take a detour.
He received some important information about the situation concerning Ethan. Although Richard was worried for the silver head—considering what Eleanor tried today, she could do worse than that—he didn't force him to come back.
The silver head has changed and matured in very little time, and when he had made a decision for himself, it would have been unfair to demand him to change his decision.
