To clear up a few things that have crept up over the weekend.
Public records search shows the security officer carries a level III license (armed officer) through the TX DPS. He'll be fine with that.
Second, the security officer was under contract, uniformed and working on post at the time of the shooting.
Something to remember. A lot of the places security officers get contracted to, especially the deep night posts, don't provide facilities for the security officer. It is not unusual for their car to be the only place for them to sit.