Landren (Burrowed Time)
From Tardis Wiki, the free Doctor Who reference
Professor Landren was an Archaeologist who specialised on transport systems. He was hoping to find a missing train of a lost civilisation. He went missing before Bernice Summerfield fell down the hole under the trench. The Unbound Doctor found him in the same hole when he went in after Benny. He was dragged into the walls by strange creatures. (AUDIO: Burrowed Time)