He doesn't have to. I worked in retail before and I felt like celebrating after I quit.
so everyone always locks the door? even if one person needs something from the washroom they would always wait till the other person finishes?
I think it's just a corridor.
Sorry I don't know if I explained myself well. I was trying to say that it is possible to put all of your upgrades on tier 5 weapons 100% of the time. You just need to survive long enough. You need luck if you want a +3 tier 5 weapon to spawn, but you don't need luck to get some random tier 5 weapons.
Edit: There are ways to survive even the final boss fight without a good weapon/armor. I think it's worth your time to find other ways to survive longer without using the Scroll of Upgrade. This way it is guaranteed that you will end up with a tier 5 weapon/armor.
I'm not saying these are bad suggestions at all, I just want to share my perspective. In my experience, it is completely feasible to acquire every item on every floor without using any Scroll of Upgrade. I don't really know how other people play this game (and I'm not saying there is a right or wrong way to play it), but I usually explore every floor before I use any Scroll of Upgrad because I want to use all of them on the strongest weapon/armor. There is almost never a single time that I don't at least find a +1 tier 5 weapon and armor. Again I'm not saying you have bad suggestions, I just don't know if it's necessary to make the game easier.
"Nothing" is peace for some people.