In the Doctor Who episode "The Time of the Doctor", the town of Christmas is attacked by a wooden Cyberman.
How did the Doctor defeat it?
We see the Doctor use his Sonic Screwdriver then inform the Cyberman that he'd reversed his flamethrower. He then challenges the attacker to confirm it as the truth field already ensures he's not lying.
The Cyberman is promptly defeated leaving the Doctor to comment: "It doesn't work on wood."
If the Screwdriver doesn't work on wood (as we've seen before) how did he defeat the Cyberman? If it does how did he lie about it?