My opinion :
That was a mission. A mission has a target and should be acomplished.
During their way , those 109's encountered both of you.
What did you expect? To be a total engagement? That was a normal decision : the leader kept both of you busy with those 2 planes and finaly with one plane. In this time they were able to reach their target.
They didn't run away from you, they had a mission to acomplish and they fooled you.