I fully agree.
When i first watched the sirens episodes. It was like 2 episodes long adventure and in the end when the sirens showed up they really creeped me out. And that head cut, in the end is just epic.
Plus the funny thing is the scotsman calls them "She Dogs"
Thats the old Cartoon Network where you could say Bitch without being held for it. LoL.
And if the scotsman wasnt there in this episode, This episode would have gone real dark and scary.