9 ▁minutes ". ▁Similarly , ▁Wilson ▁pra ised ▁the ▁writers ▁for ▁ach ieving ▁" gen u ine ▁po ign ancy " ▁in ▁half ▁an ▁hour , ▁and ▁critics ▁in ▁the ▁Metro ▁said ▁that ▁the ▁episode ▁" pack s ▁more ▁drama ▁and ▁susp ense ▁into ▁ 3 0 ▁minutes ▁than ▁many ▁a ▁five - part ▁series ". ▁Mul kern ▁said ▁the ▁episode ▁was ▁a ▁" super b ▁piece ▁of ▁drama , ▁im bu ed ▁with ▁an ▁increasing ▁sense ▁of ▁dread ". ▁The ▁story ' s ▁ending ▁was ▁pra ised , ▁with ▁D ess au ▁saying ▁that ▁" One ▁of ▁the ▁skills ▁of ▁actor / writ ers ▁Re e ce ▁She ars m ith ▁and ▁Steve ▁P ember ton ▁is ▁the ▁way ▁they ▁plant ▁se eds ▁and ▁gradually ▁leak ▁out ▁details . ▁They ▁do ▁it ▁so ▁expert ly ▁here ▁that ▁one ▁really ▁doesn ' t ▁see ▁what ▁is ▁coming ." ▁Mc D ow all ▁expressed ▁a ▁similar ▁thought , ▁saying ▁that ▁the ▁" writ ers ▁so ▁clever ly ▁threw ▁us ▁off ▁the ▁sc ent , ▁making ▁the ▁event ual ▁real isation ▁so ▁ag on ising ". ▁Wilson ▁called ▁the ▁ending ▁" dev ast ating ▁and ▁un for ese en ". ▁ ▁B enn ion ▁pra ised ▁the ▁performances ▁of ▁Smith ▁and ▁R iley , ▁but ▁said ▁that ▁Smith ▁was ▁" und ou bt edly " ▁the ▁star ▁of ▁the ▁show . ▁V icki ▁Power , ▁writing ▁for ▁the ▁Daily ▁Te legraph , ▁agreed ▁that ▁Smith ▁was ▁the ▁star , ▁calling ▁her ▁" br illiant ",