Killer images.
To beat security you need to do what we did at Beth Steel; observe and know their tactics.
I'd take a pair of tactical binoculars with me to give me an edge at Beth.
Lol, the guards many time would sit in their truck inside a garage door that face the blast furnaces from a block away. Even with the naked eye they could easily see movement on the superstructure. Sometimes they would sit in the furnace buildings with their truck parked below but that was rare.
Your guard has favorite vantage points that offer him a large field of view and/or critical areas you need to cross to access place in the plant that people like to go there.
You need to find his hiding spot (s) and avoid his "killing zones". If he's not in his normal hiding spots, he's either on break or roaming; look out.
If you smoke, don't while there. You can smell it a klick away. Dead giveaway.
A few cams or motion sensors are another possibility. Look for them. Active power is always a bad sign...
Try to do your moves in low areas and stay concealed as much as possibly.
Luckily for you it's just a game to him and he's not jacking you up with charges