When I call a function, It doesn't run completely

So this is a really weird occurrence for me, I've never had something like this happen. The function is being called from my weapon manager script, and it is to pick up the weapon. All it's doing is assigning it to some indexing array GameObject variables, calling the deploy function in the game object attached to the player, and then destroying the GameObject. The code works, however for some reason the first time I press the action key, it calls the Deploy() function (but doesn't run it fully) and also doesn't destroy the game object. The second time I press it, the game object is destroyed, and the rest of the deploy function is played.

Is this perhaps because the button call is only on the frame? I was to the understanding if a function is called, it is ran in its entirety. Code posted below:

Weapon Manager Script:

 void Update()
 {
     if (Physics.Raycast(cam.position, cam.forward, out hit, distanceToPickup))
     {
         if (hit.collider.tag == "Weapon" && Input.GetButtonDown("Action"))
         {
             WeaponIndex index = hit.collider.GetComponent<WeaponIndex>();

             if (currentGun != null)
             {
                 currentGun.GetComponent<Firearm>().Deselect();
             }

             AvailableWeapons[index.weaponIndex] = WeaponsInGame[index.weaponIndex];
             AvailableWeapons[index.weaponIndex].GetComponent<Firearm>().Deploy();

             Destroy(hit.collider.gameObject);

         } else if (hit.collider.tag == "Weapon")
         {
             Debug.Log("Press E to pickup");
         } else {
             Debug.Log("You're staring at nothing");
         }
     }
 }

Weapon Script (Called "Firearm"):

 public void Deploy()
 {
     gameObject.SetActive(true);

     aSource.clip = deploy;
     aSource.Play();
     //play deploy animation
 }