http://en.wikipedia.org/wiki/Regional_Security_Officer If in this case he did not act(which from reports I think he did move the Ambassador to the "safe room") or more likely did not have resources at his disposal(they usually do not have many) then it is possible that another organization ignored normal protocol and acted because well somebody had to. It doesn't surprise me that some nearby folks with experience in such situation went to the sound of the guns because that is the kind of guys they are. In this case those guys happened to be on the payroll of the CIA it appears.
I have mentioned in another thread that I personally don't think the upper levels of the Administration have any place in how the tactical decisions played out that night. I would be curious as to what the contingency plan was for a case like this playing out. It does seem to me that is the bigger issue in this case.