kisrael's got a good point. I bet the guy was a bar keep or something. Or was trying to block his conversations from the govment or aliens.. take your pick.
As for how many caps? As a engineer I must pick up the thrown down gauntlet.
From the doors 7 feet by 4 feet and estimating the depth as 4 doors deep or 16 feet. We have surfaces of:
two doors 4x7x(2) = 56sqft
back wall = doors - window 2x1.5= 53sqft
ceiling 8x16 = 128sqft
walls 7X16x(2) = 224sqft
Total Surface Area = 56+53+128+224 = 461sqft
Bottle caps on one half of a door: 26 high by 43 wide.
Because of the zigzag nature that means 25x43 caps = 1075caps
1075caps/4ft x 3.5ft (of half door) = 76.8caps/sqft
Drum roll please..
461sqft x 76.8caps/sqft =
35,398 caps 
Now one "bottle per day" 35,398/365 = 97years worth of bottles. Or in today's numbers, at say $2.00 per bottle, $70,796 worth of bottles.