Roots: The works of Oscar Wilde (Knox assumed his identity and rehearses The Importance of Being Earnest, the Doctor quotes from The Picture of Dorian Gray). Knox's TARDIS plays Offenbach's Orpheus in the Underworld, popularly known as the Can-Can. Knox refers to his various temporal entertainments of various aliens as a 'magical history tour', a play on The Beatles' Magical Mystery Tour.
Dialogue Disasters: Ross brings out the stage gags for a bi-centennial run: "Is it true your Bottom was a marvel to behold?"
"Imagine it Lizzie - you and me sittin' in our plantation, sippin' whiskey. Cotton pickers serenadin' us in the southern sun, singin' Polly-Wally-Doodle all Day..."
Technobabble: The Doctor resets Knox's TARDIS's galactic positioning system.
Continuity: Knox's TARDIS appears to be the same Type 70 previously used. It adopts the outward appearance of the Chinese conjuror Chung Ling Soo's magic box 'down to the last bullet-hole' and a thorny bush. It features a metal lift and a sick bay on floor Gamma Seven — Knox operates the ship via voice control and a metal lift. The Doctor proves not so well-adjusted to such an advanced model.
Knox wears a silk cravat (which he finds another use for) and claims he has a bad back due to a war wound he suffered during the Charge of the Light Brigade after his bayonet snagged in his new cardigan and he fell off his horse. Having been infected by the flu virus back in Edinburgh (Medicinal Purposes) he was unable to find a cure, and with mere hours to live sought to prolong his vitality through the intervention of a creature he found trapped in a crater of congealed iron magma on Mercury's southern lava field — an individual of the Indo.
Sustained by the creature after his eventual death Knox promised it the 'Henry Booth Experience' if it would keep him alive long enough to reach Earth. Having brokered the deal he then contained it in an iron cage within his TARDIS. Unbeknownst to Knox, other individuals of the indo [possibly members of the same refugee community which reached Brighton] were drawn by the misery and pain caused by the American Civil War. Upon the moment of Knox's arrival his captive reached out into the psychic ether and called out to its kin.
The Doctor says that Booth's death is no guarantee of Lincoln's survival — Time will be working silently to repair the damage Knox has done.
Links: Medicinal Purposes, Pier Pressure. The Doctor was present at the Charge of the Light Brigade, as revealed in Evil of the Daleks. Knox engages his TARDIS's Fast Return switch (Inside the Spaceship)
Location: Washington DC, April 14th 1865
Untelevised Adventures: The Doctor implies that he saw The Importance of Being Earnest in its theatrical premiere on 14 February 1895 at the St. James's Theatre in London. He was also present on the night when Ling Soo died during his bullet catching act at the Wood Green Empire in 1918.
The Bottom Line: After the impressive debut of the Knox character in Medicinal Purposes a rematch should have been something to look forward to, but with so much time having passed and with the storyline here being not much chop; the play seems very long and there's a sense here of an opportunity (and perhaps an audience) missed. The Indo's plan to resume the war with the martyrdom of an onlooker is ambitious at best, and at least fanciful. With Knox seemingly escaping to commit further crimes the door remains open — but perhaps it's time to move on?