Board Thread:Speculation House/@comment-27404492-20170918133425/@comment-26397825-20170925060406

Honestly, it didn't even have to be a big, planned thing. It could have simply been a A to B delivery mission (protecting supplies or whatever) and one of Salem's agents just happened to cross paths with Summer. Summer didn't even need to be suspicious of them; if Ozpin wasn't in Oscar's head, there wouldn't be anything to say "Hazel is a bad guy" beyond him punching a ticket machine.

Basically it could have been an attack of opportunity; Salem's lot didn't expect to meet a Silver Eyed Warrior out on a mission alone, but they did and took the chance they had to attack her. A sneak attack can do a lot of damage - as evidenced by Coco being knocked out by a sneak out to a vulnerable area (the junction of the neck and shoulder) by Emerald - and weakened Summer enough that they were able to kill her without dying themselves. Summer wasn't expecting it which is why she went down easier to them; she'd be more on the lookout for bandits and Grimm than someone that she passed by and seemed polite enough at the time that she didn't give them more than a cursory suspicion before putting them out of her mind.