the Shadow's power. Drax again uses the stabiliser, this time to return them to their normal size. The Doctor snatches the partially assembled Key and the final segment, and disappears with Romana and K9 in the TARDIS, assembling the Key after setting up a shield around Zeos to deflect the Marshal's missiles towards the Shadow's base, destroying it. The White Guardian appears to congratulate the Doctor on finding and assembling the Key to Time, and requests that it be sent to him. However, the Doctor, realising that it is actually the Black Guardian in disguise, orders the Key to re-disperse. Enraged, the Black Guardian threatens to kill him. In an attempt to evade him, the Doctor fits a randomiser into the TARDIS guidance system, sending it to an unknown location in time and space, leaving the Doctor with no idea of where they are headed, and the Guardian being unable to follow. Broadcast and reception Paul Cornell, Martin Day, and Keith Topping gave the serial an unfavourable review in The Discontinuity Guide (1995), describing it as "a dreary end-of-season Oh-my-God-the-money's-run-out 'spectacular'" without subtle acting. In The Television Companion (1998), David J. Howe and Stephen James Walker wrote that The Armageddon Factor was "entertaining enough in itself, with some good direction by Michael Hayes and generally fine production values, but ultimately fails to tie up all the loose ends and leaves the over-arching plot strangely unresolved". They praised the Shadow but felt that the other characters were one-dimensional, and called the ending a "cop-out". In 2011, Patrick Mulkern of Radio Times stated that the serial "hugely disappoints, yet it's not an unmitigated disaster". He criticised the characterisation and much of the plot, but praised the direction and the Shadow. On the other hand, DVD Talk's Justin Felix gave the serial four out of five stars, saying that it "packs more of a wallop than the previous two stories" and had everything typical of Doctor Who. Felix also called it Mary Tamm's best performance. Commercial releases In print A novelisation of this serial, written by Terrance Dicks, was published by Target Books in June 1980. Home media Along with the rest of season sixteen, it was released on DVD in North America as part of the Key to Time box set in 2002, only available in Region 1. A remastered limited edition Key to Time box set was released in Region 2