God, this question sucks. I think it's like a 3 or 4 out of 10, just because it's extremely subjective and 10 would be fucking Jonestown or the holocaust or John Wayne Gacy/Ed Gein, etc.
But if I say that now I look like a rape apologist lol.
Or are we rating it compared to other scenarios of rape? In that case, like a 4-5 -- 10 would be something like a mass gang rape with extreme brutality, etc.