delta time is not working right (freezed)

Hello, My script should work that on collision an bool is called, and if bool is called, for certain time a speed of gameobject has to be different. I created it and I bet it should be working, but it isnt... No idea why. Code: float randX; float randY; Vector3 whereToSpawn;

     public GameObject bonus1;
     float spawnRatebonus1;
     public Player1Script otherScript;
     public Player2Script otherScript2;
     public bool newspeedactivated;
     public float TimerBonus = 15.0f;
     public bool plr1end;
     public bool plr2end;
 
     // Use this for initialization
     void Start () {
         spawnRatebonus1 = Random.Range(10, 15);
         
   
     }
     
     // Update is called once per frame
     void Update () {
 
         spawnRatebonus1 -= Time.deltaTime;
 
         if (spawnRatebonus1 <= 0)
 
         {
             
             randX = Random.Range(281, 1747);
             randY = Random.Range(132, 790);
             whereToSpawn = new Vector3(randX, randY, -1);
             bonus1.transform.position = whereToSpawn;
             spawnRatebonus1 = Random.Range(10, 15);
             bonus1.gameObject.SetActive(true);
             
 
             
         }
 
         if (newspeedactivated == true)
         { TimerBonus -= Time.deltaTime; }
 
         if (TimerBonus <= 0)
         {
             otherScript.speed = 50f;
             otherScript2.speed = 50f;
         }
 
 
 }
 
 
 void OnCollisionEnter2D(Collision2D collision)
     {
         
 
         if (collision.collider.tag == "Player1")
         {
             Debug.Log("Player1SpeedUp");
             otherScript.speed = 85.0f;
             newspeedactivated = true;
             plr1end = true;
             
 
 
         }
 
         if (collision.collider.tag == "Player2")
         {
             Debug.Log("Player2SpeedUp");
             otherScript2.speed = 85.0f;
             newspeedactivated = true;
             plr2end = true;
         }
 
 
         bonus1.gameObject.SetActive(false);
        
 
     }
    
 
 }