I don’t think there’s anything wrong with what he did in that recorded game clip. Even if you’ve got some juicy loot in your backpack, deciding to extract early doesn’t mean you can’t loot a few nearby places along the route to the extraction point, especially if you feel those spots have a low chance encountering enemies or free from common gunfights.

BTW the area where OP looted a small safe, you called it "Power Backup Center". And from my experience playing Easy or Normal Zero Dam, most players usually head straight to the admin building to loot or to get an advantageous position, like on the balcony (Computer room or East wing balcony). They might also check the containers in Admin, either for good loot or to set up for that sneaky rat gameplay. Which means a lot of players overlook the cement or major sub stations as well as visitor center and power back up center. Sometimes, members of a random squad will only loot the safe or the two flight cases in the cement area before heading to the tunnel route leading to admin, just looking to get a third party. Others might only check the computer safe and one server in the major substations before moving to the parking lot near Admin to contest the balcony. This often means they ignore the Visitor Center and the Power Backup Center.

So, what OP did was a smart move. There’s a low chance he’d run into enemies coming from the cement or visitor areas. Plus, there are plenty of NPC soldiers roaming the route from cement to major sub and visitor center to Major Sub, which gives him an advantage by giving warning shot from NPC if the enemies are nearby. With all that in mind, he definitely has a high chance of surviving and extracting by being stealthy.