Deadlock seals are mentioned again in "School Reunion" (2006), "Evolution of the Daleks" (2007), "42" and are the only kind of seals that a single Sonic Screwdriver is incapable of penetrating alone.
Deadlock seals are mentioned again in "School Reunion" (2006), "Evolution of the Daleks" (2007), "42" and "The Time of Angels". They are the only kind of seals that a single Sonic Screwdriver is incapable of penetrating alone.