Two more indispensible modern Doctor Who episodes are shown tonight, accompanied by behind-the-scenes info, are shown in prime time tonight. The first is The Time of the Doctor, the show’s 2013 Christmas Day special, the one that handed off the title role from Matt Smith to the current Doctor, Peter Capaldi. Then, at 9:45 p.m. ET, is 2010’s Doctor Who: A Christmas Carol, the show’s 2010 Christmas special, a Matt Smith episode featuring, as its surly Scrooge-like character, the great Michael Gambon.