A question about updating routing tables

[hot9cups]

I know this project is 2 years old now, and perhaps no longer maintained but just in case;

In the code for updating the routing tables, this very specific line, why do we assign 16 to interDist if inter[i][j] is equal to source? inter[i][j] == source is true only when i is equal to j, and so route[i][j] would be 0. So interDist + route[source][j] would be equal to 0 + route[source][j]. Why is that a problem? Why do we have to assign 16 to interDist whenever that happens?