BAKER: Doctor! I shouldn't worry about him, Brigadier. The DOCTOR looks uncomfortable for a minute, then continues his conversation with the OLD SILURIAN.) The YOUNG SILURIAN turns to the SCIENTIST, and then leaves the control room.)
Plan: A: the Doctor; Q: Who does the Old Silurian have a growing friendship with? A: the scientist; Q: Who did the Young Silurian have infect Baker with a virus? Summary: Worried about the Old Silurian's growing friendship with the Doctor, the Young Silurian has the scientist infect Baker with a virus and then release him.