SPEMack618, I can't say for a certainty what he did while deployed to Bahrain, but having worked at 5th Fleet HQ a decade ago, I can make a reasonably educated guess as to the upper limit of Rambo-ness he could have experienced.
He might have had some role with harbor security, but a mobilized Reserve O-3 would be in a primarily administrative function with them. They might occasionally let the LT ride around in a boat, once in a while.
He might have had some role with EOD, but again since that was not his specialty, he would have been administrative. They might have taken him on the occasional range day, if they liked him.
From what I read, he was qualified Expert in pistol, but only Marksman in rifle. That does not indicate high speed, low drag. I qualified Expert in rifle the first time the Navy let me shoot one, which was a decade into my career. Not many specialties get much rifle time in the Navy; those that do would all qualify higher than Marksman - or they really should.
I have also read a couple comments from unnamed LA law enforcement types that indicated Dorner had some aviation training. If so, that would imply that he had washed out of either Pilot or NFO training at some point; if that is so, he would likely have been administratively separated due to over-manning, and thus entered into Reserve status as an unspecialized line officer.
Back when the budget could support it, a lot of aviation wash-outs would get sent out to aircraft carriers to be admin/clerk types in Air Operations. Students that couldn't handle some aspect of aviation training, but who worked hard and earned the respect of their instructors, would sometimes get better billets - we sent one that I recall off to Intel school, where he thrived; another went to SWOS. Most just ended up unspecialized and, career-wise, dead in the water.
Of course, I am just speculating based on limited information in news articles, and the implications of what little was said.