How to call function from this script?

As the title suggests I am trying to call a function from another script in my footstep manager script. I am trying to activate a sphere collider everytime I take a step to simulate sounds that can be heard by enemies. I have already figured out where to do this and have a Debug.Log displaying for every step. I typically code in js so I am having alot of trouble with this. I have tried adding my sphere collider to a variable at the top of the script but it will never show in the inspector for some reason. I obviously did not write this code it was part of a package I own but any help would be greatly appreciated.

It is at line 136 under protected virtual void Footstep()

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 
 public class vp_FootstepManager : MonoBehaviour
 {
     public GameObject myCollider;
     /// <summary>
     /// surface type object for storing sounds in relation to textures
     /// </summary>
     [System.Serializable]
     public class vp_SurfaceTypes
     {
         public Vector2 RandomPitch = new Vector2( 1.0f, 1.5f ); // random pitch range for footsteps
         public bool Foldout = true; // used by the editor to allow folding this surface type
         public bool SoundsFoldout = true; // used by the editor to allow folding the sounds section
         public bool TexturesFoldout = true; // used by the editor to allow folding the textures section
         public string SurfaceName = ""; // Name of the surface for reference in the editor
         public List<AudioClip> Sounds = new List<AudioClip>(); // List of sounds to play randomly
         public List<Texture> Textures = new List<Texture>(); // list of the textures for this surface
 
     }
     
     static vp_FootstepManager[] m_FootstepManagers;
     public static bool mIsDirty = true;
     /// <summary>
     /// Retrieves the list of item databases, finding all instances if necessary.
     /// </summary>
 
     static public vp_FootstepManager[] FootstepManagers
     {
         get
         {
             if (mIsDirty)
             {
                 mIsDirty = false;
                 
                 m_FootstepManagers = GameObject.FindObjectsOfType(typeof(vp_FootstepManager)) as vp_FootstepManager[];
                 
                 // Alternative method, considers prefabs:
                 if(m_FootstepManagers == null)
                     m_FootstepManagers = Resources.FindObjectsOfTypeAll(typeof(vp_FootstepManager)) as vp_FootstepManager[];
             }
             return m_FootstepManagers;
         }
     }
     
     public List<vp_SurfaceTypes> SurfaceTypes = new List<vp_SurfaceTypes>(); // list of all the surfaces created
     public bool IsDirty{ get{ return mIsDirty; } }
     
     protected vp_FPPlayerEventHandler m_Player = null;        // for caching the player
     protected vp_FPCamera m_Camera = null;                    // for caching the FPCamera
     protected vp_FPController m_Controller = null;            // for caching the FPController
     protected AudioSource m_Audio = null;                    // for caching the audio component
     protected AudioClip m_SoundToPlay = null;                // the current sound to be played
     protected AudioClip m_LastPlayedSound = null;            // used to make sure we don't place the same sound twice in a row
     
     
     /// <summary>
     /// cache all the necessary properties here
     /// </summary>
     protected virtual void Awake()
     {
         
         m_Player = transform.root.GetComponentInChildren<vp_FPPlayerEventHandler>();
         m_Camera = transform.root.GetComponentInChildren<vp_FPCamera>();
         m_Controller = transform.root.GetComponentInChildren<vp_FPController>();
         m_Audio = gameObject.AddComponent<AudioSource>(); // add a new audio source for this class to use
     }
     
     
     public virtual void SetDirty( bool dirty )
     {
         mIsDirty = dirty;
     }
     
     
     /// <summary>
     /// 
     /// </summary>
     void Update()
     {
 
         // if the camera bob step callback is null for some reason,
         // add our footstep callback again
         if (m_Camera.BobStepCallback == null)
             m_Camera.BobStepCallback += Footstep;
 
     }
     
     
     /// <summary>
     /// 
     /// </summary>
     protected virtual void OnEnable()
     {
         
         // add the footstep callback
         m_Camera.BobStepCallback += Footstep;
         
     }
     
     
     /// <summary>
     /// 
     /// </summary>
     protected virtual void OnDisable()
     {
         
         // remove the footstep callback
         m_Camera.BobStepCallback -= Footstep;
         
     }
     
     
     /// <summary>
     /// Here is where we check to see if the texture
     /// under the controller is assigned to a surface.
     /// If so, play a sound.
     /// </summary>
     protected virtual void Footstep()
     {
         Debug.Log ("FootStep");
   
         // return if the controller is not on the ground
         if(!m_Controller.Grounded)
             return;
         
         // return if there no texture or surface type is found
         if(m_Player.GroundTexture.Get() == null && m_Player.SurfaceType.Get() == null)
             return;
         
         if(m_Player.SurfaceType.Get() != null)
         {    
             PlaySound( SurfaceTypes[ m_Player.SurfaceType.Get().SurfaceID ] );
             return;
         }
         
         // loop through the surfaces
         foreach(vp_SurfaceTypes st in SurfaceTypes)
         {
             // loop through the surfaces textures
             foreach(Texture tex in st.Textures)
             {
                 // if the texture is the same as the ground texture...
                 if(tex == m_Player.GroundTexture.Get())
                 {
                     // play random surface sound
                     PlaySound( st );
                     break;
                 }
             }
         }
         
     }
     
     
     /// <summary>
     /// Plays a random sound from the surface the
     /// controller is currently over
     /// </summary>
     public virtual void PlaySound( vp_SurfaceTypes st )
     {
         // return if there are no sounds
         if(st.Sounds == null || st.Sounds.Count == 0)
             return;
         
         reroll:
         m_SoundToPlay = st.Sounds[Random.Range(0,st.Sounds.Count)]; // get a random sound
         
         // if the sound is null, return
         if(m_SoundToPlay == null)
             return;
         
         // if the sound was the last sound played, reroll for another sound
         if (m_SoundToPlay == m_LastPlayedSound && st.Sounds.Count > 1)
             goto reroll;
         
         // set a random pitch
         m_Audio.pitch = Random.Range(st.RandomPitch.x, st.RandomPitch.y) * Time.timeScale;
         m_Audio.clip = m_SoundToPlay;
         m_Audio.Play(); // play the sound
         m_LastPlayedSound = m_SoundToPlay; // cache this sound
         
     }
     
     
     /// <summary>
     /// Returns the zero-based index of the most dominant texture
     /// on the main terrain at this world position.
     /// </summary>
     public static int GetMainTerrainTexture(Vector3 worldPos, Terrain terrain)
     {
         
         TerrainData terrainData = terrain.terrainData;
         Vector3 terrainPos = terrain.transform.position;
  
         // calculate which splat map cell the worldPos falls within (ignoring y)
         int mapX = (int)(((worldPos.x - terrainPos.x) / terrainData.size.x) * terrainData.alphamapWidth);
         int mapZ = (int)(((worldPos.z - terrainPos.z) / terrainData.size.z) * terrainData.alphamapHeight);
  
         // get the splat data for this cell as a 1x1xN 3d array (where N = number of textures)
         float[,,] splatmapData = terrainData.GetAlphamaps(mapX,mapZ,1,1);
  
         // extract the 3D array data to a 1D array:
         float[] mix = new float[splatmapData.GetUpperBound(2)+1];
         for (int n=0; n<mix.Length; ++n)
         {
             mix[n] = splatmapData[0,0,n];    
         }
   
         float maxMix = 0;
         int maxIndex = 0;
  
         // loop through each mix value and find the maximum
         for (int n=0; n<mix.Length; ++n)
         {
             if (mix[n] > maxMix)
             {
                 maxIndex = n;
                 maxMix = mix[n];
             }
         }
  
         return maxIndex;
  
     }
     
 }