There is something that I've wanted to know for a while now. So Valeris won't tell the names of her co-conspirators, so Spock uses a forcible mind-meld on her to get the names. Then Kirk asks for the location of the conference, so Spock digs deeper (which causes great distresses for them both). She doesn't know, so Kirk contacts Sulu, and he knows. Why didn't Captain Kirk or Spock just get in contact with Captain Sulu for those details?
Sulu wouldn't have any idea about who the conspirators were.