Yeah, but you don't need to know/remember who the person you are killing is to finish killing them. Especially if you're a dalek.
The daleks want to kill every other living thing. If they're in the middle of killing someone, they don't just.... Stop because they don't know the person.
you cant plot to kill something that you dont remember, simple as. you dont even know they exist.
You don't know they exist despite the fact that he's right in front of your face?
PS: love Matt Smith! Favourite doctor!
PPS: the way the daleks say "DDDDDOOOCCC-TTTTOOOORRRR!" is really creepy. They're like zombies! I'd be pretty scared if the daleks started saying my name like that! "TTTHHHEEE NNNAAAMMMEEE MMMAAASSSTTTEEERRR!" Or on second thoughts, I might lol!