There are exactly 3,125 possible code combinations (yes there are 10 numbers, but only five buttons. The key pad doesn't know if you're pressing for a 1 or 2. It just knows that button was pushed.)
If the pic in the first post holds true and the key pad only holds the last 5 key presses in memory then we can deduce that one would be able to try 31 codes before the anti scan feature kicked in. You then have to wait 1 minute to try again. Say you're really fast at pressing the correct keys and can do 1 a second. That puts it at 95 seconds from the time you start pressing keys, before you can enter the next 31 codes, and so on.
Sooo... 7 minutes? Maybe if you get lucky and get the code in the first 175 key presses, but that's not too likely. Let's assume the correct code is the last 5 button combinations you try. That's approx 2 hours 39 minutes and 37 seconds. Chances of getting it that late in the game are pretty small too.
So let's just say, using the posted method and taking the anti-scan feature into account, it could take a reasonably talented and prepared thief anywhere from 5 seconds to 2 1/2 hours to crack your door code
Just for comparisons sake, if all 10 numbers actually counted, there would be 100,000 possible 5 number combinations and a max of over 85 hours to try them all. What if letters were included? 60,466,176 possible 5 character combos and a max of over 5 years and 10 and a half months.
Ok... Math lesson over! Hahaha.