It is because your branch checks for pess than or equal to the last index (length - 1) of the patrol points. that means the False branch only happens when the index is MORE than the last index of the patrol points, which cannot happen unpess you increased it to be out of range which would cause errors on your Get node on the left side.
try changing it to a < (less than) instead of a <= (less than or equal to) node.
remember an array of size 3 will have indexes 0, 1, and 2.
So length - 1 equals 2.