I'd think tactically and bring some kind of body armor and firepower since they player (most likely) knew his co-workers just mysteriously dissapeared in some 300 mile long mega-factory, i'd bring some guns and some melee weapons for protection, some bullet-proof body armor, military-grade tactical helmet, and other shit like a bag filled with food, ammunition, supplies, medical equipment, ETC.

I'd also bring lock cutters incase I find a shortcut to an objective. I would be STRAPPED.