Lever

the Master pulling a lever with the intent of dropping the Doctor and Emma into the sewers of Tersurus. (TV: The Curse of Fatal Death)

Nauseated by the prospect of the Doctor and his companion, Emma, getting married, the Master announced that he would go back in time, buy the architect an expensive dinner and persuade him to place a lever next to where he was standing and a trap door where the Doctor and Emma were standing. He prepared to plunge them into the vast and disgusting sewers of Tersurus, warning them to prepare themselves for "five hundred miles of fear and faeces!"

When the Master pulled said lever, the trap door opened under his own feet, the Doctor having bought the architect an expensive dinner earlier. (TV: The Curse of Fatal Death)

A house flown above by E.T. on a red flying machine resembling a phone had a black lever with yellow handles and a red light. (WC: Supergirl Meets E.T.)

Behind the scenes

Information from invalid sources

Kevin pulling a lever in the TARDIS. (NOTVALID: Mind My Minions)

While in the TARDIS, Greg James shouted at Kevin, a Minion, not to pull a lever. Kevin then pulled it anyway, transporting Greg, Kevin, Stuart, and Bob back to 1953, also causing the TARDIS's appearance to change, causing everything to appear in black and white, and causing a Dalek to appear in the TARDIS behind Greg. Greg then pulled another lever, taking the group to Coronation Street. (NOTVALID: Mind My Minions)