Ok so essentially what you do is, as soon as the Fight starts you go next to the damage power up, but dont pick it up yet just in case it last an pretty short time.
Now equip the telefragger and fully charge it, what happens here or more accurately in which order kinda depends on what ripper does / where she is positioned but essentially as soon as you see her you pick up the power up and activate your slow-mo shoot her and repeat and she will die after only 2 shots super easy and pretty much fool proof, even on murder machine

Thanks for reading and sorry for the low appeal of the guide, it was my first one ever and any tips like formating and stuff would be apreciated