Vector2.lerp dashing problem

Im making a 2D platformer game, where the player dashes back and forward. Now I want it that the player dashes randomly up and down or back and forward.

So far I made the player dash back and forward only up and down is missing:

         player.transform.position = Vector2.Lerp (enemy.transform.position  * 0.9f, enemy.transform.position, 0.5f);
         enemy.GetComponent<Enemy> ().sliceeffect();
         yield return new WaitForSeconds (0.1f);
         player.transform.position = Vector2.Lerp (enemy.transform.position  * 1.1f, enemy.transform.position, 0.5f);
         enemy.GetComponent<Enemy> ().sliceeffect();
         yield return new WaitForSeconds (0.1f);
         player.transform.position = Vector2.Lerp (enemy.transform.position  * 0.9f, enemy.transform.position, 0.5f);
         enemy.GetComponent<Enemy> ().sliceeffect();
         yield return new WaitForSeconds (0.1f);
         player.transform.position = Vector2.Lerp (enemy.transform.position  * 1.1f, enemy.transform.position, 0.5f);
         enemy.GetComponent<Enemy> ().sliceeffect();
         yield return new WaitForSeconds (0.1f);
         player.transform.position = Vector2.Lerp (enemy.transform.position  * 0.9f, enemy.transform.position, 0.5f);
         enemy.GetComponent<Enemy> ().sliceeffect();
         yield return new WaitForSeconds (0.1f);
         player.transform.position = Vector2.Lerp (enemy.transform.position  * 1.1f, enemy.transform.position, 0.5f);
         enemy.GetComponent<Enemy> ().sliceeffect();
         yield return new WaitForSeconds (0.1f);
         player.transform.position = Vector2.Lerp (enemy.transform.position  * 0.9f, enemy.transform.position, 0.5f);
         enemy.GetComponent<Enemy> ().sliceeffect();
         yield return new WaitForSeconds (0.1f);