4 digit pin in a 20 digit entry. Security issue

So this is not for homeworkor anything it is an issue that came up at work that has nothing to do with my line of work but I was somehow involved. Hoping you great people can help me out. We have a lock system that is protected by a 4-digit code which I know gives 10000 possibilities. There is a so-called security feature if there is someone peaking over your shoulder that allows you to enter 20 digits and as long as your 4-digit code is somewhere in there then when you hit enter it will work. My question is does this now make it easier to access the lock? And whats the math behind it?