The murder of the guard causes the four time-travellers to momentarily stop and reflect. It’s fascinating (and slightly disconcerting) that the Doctor asks Ian quite seriously whether he killed him – if Ian said he had it’s probable that the Doctor wouldn’t have been terribly put out. Another interesting character wrinkle is that although the camp seems to be under attack, the Doctor is still keen to escape (clearly the fates of Marco and Ping-Cho are of little interest to him).

Tegana’s appearance puts paid to their plans, so Ian decides to wake Marco and warn him. I’ve previously touched upon how Tegana’s numerous attempts to kill Marco end up being scuppered (sometimes in a slightly contrived way) and this sequence is one of the less convincing ones. Acromat (Philip Voss) and the other Mongols are waiting for Tegana’s signal to attack. After Ian’s warning, Marco asks Tegana to rouse the guard – but why didn’t he tackle Marco in single combat there and then? It’s difficult to believe that Tegana seriously considered the TARDIS crew to be a threat to his ambitions.

Instead, he obeys Marco and the small group organise themselves into a fighting force. Marco gives the Doctor a sword, commenting that “if you’re half as aggressive with this as you are with your tongue, Doctor, we can’t lose.” Although the Doctor is sometimes painted as a pacifist who abhors weapons of any type, that’s not really borne out by the evidence of the series – although it’s still unusual to seem him bear arms quite so keenly. The loss of the episode means that we’ve no way of telling how active he was in the brief skirmish – however, just before the fighting begins he delightfully tells Marco that “we’re not going to get very far with this overgrown bread knife!” which indicates he was keen for a scrap!

Eventually Acromat and the others grow tired of waiting for Tegana’s signal and attack anyway. This presented Tegana with another golden opportunity to kill Marco (as the Mongols were keeping the others busy). Instead, he kills Acromat before he had a chance to reveal his connection to Tegana. Again, it’s another moment that feels a little false – just how many chances does Tegana need?

The arrival of the caravans at the Cheng-Ting Way Station introduces us to Wang-Lo (Gábor Baraker). From the soundtrack and the photographs it sounds like a larger-than-life performance, this is another of those times when I’d love to see the visuals in order to complete the picture. Also lurking about is Kuiju (Tutte Lemkow). Lemkow had a lengthy career (popping up in films like Raiders of the Lost Ark) and an interesting private life (at one time he was married to Mai Zetterling). Lemkow’s Doctor Who career is rather unlucky – he appeared in three different stories (but all his episodes no longer exist). It seems that anything with an appearance by Tutte Lemkow was earmarked for destruction …

When Ping-Cho realises that Susan will never see her home again without the TARDIS, she takes the key from Marco’s room. This is when the never-ending feel of the early seasons works well – back then, unless you had a copy of next week’s Radio Times it wouldn’t always be obvious whether a story was concluding or not. But this one now seems to have run its course, as the Doctor, Ian and Barbara are all in the TARDIS – but somewhat belatedly they realise that Susan isn’t there.

She’s gone back to say goodbye to Ping-Cho, something which the Doctor finds inexplicable. Despite the months they’ve been journeying together, he’s clearly failed to notice the growing friendship between his granddaughter and Ping-Cho. It’s another character moment which highlights that recently the Doctor has been, at best, totally absorbed with repairing the TARDIS and, at worst, totally self-centered. His irritation with Susan sees him utter an oath (“Great Olympus”!) which is a little unusual.

No real surprise that the Doctor’s plan of escape is scuppered again – this time it’s because Tegana has caught Susan …..