S02E02: 'The Last Sontaran' Part Two

The stakes are high during the concluding part of the season's opening story, as Sarah Jane and her pals are holed up in the radio telescope centre. There's plenty of chasing around corridors to pad out the episode, but can you hunt down the red herring amongst the following spoilers?

Sarah Jane is shot.

One of Maria's parents doesn't survive the episode.

Luke has a gas problem.

Chrissy meets Mr. Smith.

A Sleeper Agent is on the loose.

Law Three of Sontaran Battle: Always have a Plan B.

A Sontaran's stumpy fingers are used to thwart the alien invader.