History Headscratchers / DoctorWhoSeries8

** I'm pretty sure at least one of them started to say "exterminate" or something, but was blown up. Even if they didn't, Daleks don't really seem to kill Daleks unless they're impure or something. In this case, I think they were just surprised and were struggling to understand why a Dalek (who they were sort of coming to save) would start killing them. It probably takes something drastic to make a Dalek kill another and these just couldn't react in time. I mean, when they had that planet full of insane Daleks, I'm sure it would have been better for them to be wiped out, but the 'sane' Daleks didn't want to kill them (and probably viewed them as being fantastic, if uncontrollable Daleks). They also seem to need ordered to do a lot of things and maybe found it difficult to attack without a superiorly ranked Dalek saying "stop killing humans, start killing that Dalek!".