The Ice Warriors return, as does (somewhat controversial) writer Mark Gatiss, in “Empress of Mars.” This episode felt like classic series “Doctor Who”, and piled on the old-series references too. How did we feel it measured up to this season, and to Gatiss’s previous work? How convenient was it that the TARDIS and Nardole disappeared? And was it a nice respite before we dive into late-season drama? Host Jason Snell with James Thomson.