 What do Miss Drayson and Kylen Braynek have in common?
To violate the rigid social setup of Saarkkad would mean the instant closing off of the supply of biochemical products that the Saarkkadic laboratories produced from native plants and animals—products that were vitally necessary to Earth's war, and which could be duplicated nowhere else in the known universe. Not the worst ones, of course; there were places in the galaxy that were less important than Saarkkad to the war effort. It had taken Malloy a long time to get it into Miss Drayson's head that it was perfectly all right—even desirable—for her to keep secrets from everyone except Malloy.
 They are both paranoid about what other people think.
 They externalize a lot of their thought processes.  They are constantly processing extreme amounts of details.  They both dislike interacting with other people.  They are both paranoid about what other people think.