Triumph is Enterprise. Enterprise Airways went bankrupt a few years ago when the automotive Just-in-Time business dried up; Triumph was the new company created. The reason you only saw Enterprise and not Triumph in the building is because the FBO is called Enterprise Air. Its the same group. DASL (Durham Aviation Services Ltd.) is the parent company that owns Triumph (charter company), Enterprise (FBO), and Durham Flight Centre (flight school) as well as the hangar that you were snooping around in.
Does the name gatester have anything to do with Gateway?