SIR
The padlock wouldn’t be on the door, because that is too cumbersome to remove in a hurry.
I find one that fits the criteria. A keypad instead of a padlock. 3 containers wide and 4 long, brackets and bolts connecting each one to the other. There is noise coming from inside, muffled, but audible. Walking around it, there is no way of getting inside except for the front door, it seems.
Well, here goes nothing.
I knock.
The door opens, and a middle-aged dark-haired guy looks at me.
“What do you want?” He asks.