Seiya's immediate next act was procuring all of the important vital items from within the castle interior before he destroyed the plateau and the castle atop it, not that the castle was in good shape after Mifuyu's passing.
Her existence maintained the integrity of the castle so when she passed, the castle quickly began to fall apart and no one had any power to do anything to keep it standing tall or at all for that matter.
Despite one would believe of Seiya,Tsukumo,Shoichi and Yir they ended up taking a whole day's worth of sleep after they finally had nothing left to do and the soldiers made sure that there was a tent ready for them to rest in until they woke up.
