The incident of the dungeon was kept a secret by all of them there; they understood what Lance stood to lose if this was leaked.
Everyone returned back to the academy after that. They had their fill of adventuring, and they all decided to spend the time in the academy practicing their spirit zone or something else.
Riven had been locked inside his room for days, trying to get in contact with the spirit zone and also trying to talk to Twilight, but no matter how hard he attempted to contact the spirit, it didn't work.
He had given up on the sword; he figured maybe one seal was not enough for him to get any useful information from the sword.
The issue was that he didn't even know how he unsealed the sword in the first place, so he didn't know how to go forward with the sword. He decided that the next time he had the chance, he would head to Ribest and meet Black to ask him about the sword.