Vector3.Distance returning weird distances?

So I set it up to where the enemy tank would shoot the distance so it wouldn't miss. I had it setup to where the tank would miss 45% of the time but here is the code

 using UnityEngine;
 using System.Collections;
 using UnityEngine.UI;
 using PlayerInfo;
 using Shell;
 
 namespace EnemyInfo
 {
     public class EnemyAttack : MonoBehaviour 
     {
         public float timeBetweenAttacks = 0.75f;
         public float attackDamage;
         public Rigidbody Shell;
         public Transform FireTransform;
         public AudioSource ShootingAudio;
         public AudioClip Firing;
         public float LaunchForce;
         public Transform ETank;
         public Transform PTank;
         public int missChance = 45;
 
         GameObject player;
         PlayerHealth pHealth;
         EnemyHealth eHealth;
         PlayerAttack pShoot;
         EnemyAttack eShoot;
         float timer;
         EnemyMovement eMove;
         ShellExplosion sExplo;
         bool isMiss;
         float distance;
         int randPercent;
 
         void OnEnable ()
         {
 
         }
 
         void Awake ()
         {
             player = GameObject.FindGameObjectWithTag ("Player");
             pHealth = player.GetComponent<PlayerHealth> ();
             eHealth = GetComponent<EnemyHealth> ();
             eMove = GetComponent<EnemyMovement> ();
         }
 
         void FixedUpdate ()
         {
             float distance = Vector3.Distance (PTank.position, ETank.position);
         }
 
         void LateUpdate ()
         {
             timer += Time.deltaTime;
 
             if (timer >= timeBetweenAttacks && eMove.inRange && eHealth.CurrentHealth > 0 && pHealth.CurrentHealth > 0)
             {
                 Attack ();
             }
         }
 
         void Attack ()
         {
             int randPercent = Random.Range (1, 100);
 
             if (randPercent <= missChance) 
             {
                 LaunchForce = Random.Range (30, 50);
             } 
             else 
             {
                 LaunchForce = distance;
             }
 
             Debug.Log (LaunchForce);
 
             timer = 0f;
 
             Rigidbody shellInstance = Instantiate (Shell, FireTransform.position, FireTransform.rotation) as Rigidbody;
 
             shellInstance.velocity = LaunchForce * FireTransform.forward;
         }
     }
 }

The problem I am having is the enemy tank will shoot, but it will be a distance of 0 units. No matter what I do. Unless I stick an actual number in there, it will shoot 0.