Everyone and everything abides by the law of attraction whether we are conscious of it or not. Therefore if you are constantly regarding your twin flame to be a runner then you are sending out that belief into the universe which will reflect back into your physical life as your reality. If you concentrate on your twin flame being a runner then they will become a runner.
But there's more to it than this. If you are believing your twin flame to be a runner then YOU are blocking your own energies from receiving your twin flame and reunion. You are out of alignment with the love vibration, therefore you cannot attract the love that you are desiring. You are believing that your twin flame is withholding love and so your very belief in that cuts you off from receiving that love.
You may believe that you don't have any control over your life and your twin flame's actions, but in truth, if this person truly is your twin flame then they WILL reflect your beliefs. So change your thoughts into beliefs of reunion. See your twin flame running TOWARDS you.
Sift through all your limiting beliefs and transform them into beliefs which support reunion. At first it may feel like you are lying to yourself, but if you persist then you will begin to see changes in your twin flame and your connection.
When you are believing your twin flame to be a runner then you are stuck feeling helpless and at the mercy of a "random" universe. Taking back your power means consciously CHOOSING your beliefs on a consistent basis until you actually believe and then you send out a different energy frequency. You are no longer sending out the low vibration of fear which blocks love - you will be sending out faith and trust and so you will allow yourself to receive.
So keep your thoughts and beliefs positive! Your twin flame reunion depends upon it!