But of course! He's going to need an assistant if he's to create a safe place in Cardiff - he may not have to stop to sleep or eat, but even he can't be in two places at once. And Carys is, like, the only S1 bit character who is in a position to understand more quickly about aliens and is neither dead nor evil. (Seriously, check the episode list. TW's guest characters do not have a high survival rate.)