Once the pressure from the chaser is gone, the runner misses the chase because they are not running anymore since nothing is chasing them.
The runner panics because they realize that Chaser was serious and genuine after all. They start to wonder if the chaser is going to forget about them and move on which brings more longing for their Twin Flame.
The runner realizes that they will never have such an authentic connection with anyone because their Twin Flame is Unique from everybody else that they ever knew before and after they run from their Twin Flame.
If the runner was trying to replace the feelings of being connected to their Twin Flame with other things or people, they realize how exhausting it is to try and forge that authentic connection.
This is part of the Soul lessons for the Runner Twin Flame. Every experience is an opportunity to grow the Soul.
The runner can breakdown from the heartache of missing out on a chance of an authentic relationship m, and the easiest response would be to contact their Twin Flame to rectify the situation if it is not too late.
If it is too late, the runner learns to live the rest of his life with the biggest regret of their life, missing out on their True Love.
If the runner is not completely healed within, they may be shocked by the realization of a genuine connection so they end up running further or Chase the Twin Flame counterpart instead until they learn their soul lessons.
I hope this helps.