On deathrun gmod, if you single out on person in the middle or end of a group and kill them, is that against the rules?
Only if you intend to kill that person alone and I believe it's not really that big of a deal unless you do it repeatedly
I just keep getting singled out and killed even though I am in the middle with no one else around me.
If the death is purposely only going after one person it's targeting and treated similarly to harassment/role avoiding. However, I find most the time when someone believes they're being targeted they just don't know the full story of what the death is doing. Sometimes they're being strategic, or it could be they were afk at the start of the round. Be aware that just because you die and you aren't the first person, it doesn't mean you're being targeted.