Problem using Arrayed Transforms in IEnumerator

Hi everyone,

I'm trying to write a script, that can be applied to an object, in my case a machine, that will make all the 3D parts it consists of (not the unity components) "explode" and then float in the air once you enter the trigger Collider.

The purpose is to have a better overview of the machineparts in VR and later be able to view details.

What I have in mind, should look similar to this:

For the movement of the component to the triggered position, I want to use an IEnumerator that changes the Transform[]'s position based on a Vector3.Lerp. To make it possible to add a variable number of components, I want to array the Transforms for this.

I have no real idea, why this Array in the IEnumeratordoesnt work.

Here is my code for reference:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;

 public class Explode : MonoBehaviour {

     public float time;

     public Transform[] stopTransform;
     public Transform[] startTransform;

     private Vector3[] startPosition;
     private Vector3[] stopPosition;


     // Use this for initialization
     void Start () {

         startPosition = new Vector3[startTransform.Length];
         stopPosition = new Vector3[startTransform.Length];

         for(int i=0; i < (stopTransform.Length - 1); i++){
             
             if (stopTransform[i] != null) {
                 
                 if(startTransform[i] != null && stopPosition[i] != null){
                     startPosition[i] = startTransform [i].position;
                     stopPosition[i] = stopTransform [i].position;
                 }
             }
             else {
                 this.enabled = false;
             }
         }
     }

     void OnTriggerEnter( Collider other ){
         for (int i = 0; i < stopTransform.Length; i++) {
             StartCoroutine (Expand (i));
         }
     }

     IEnumerator Expand (int p) {
         
         float t = 0.0f;

         while (t < 1.0f) {

             t += Time.deltaTime / time;

             startTransform [p].position = Vector3.Lerp (startPosition [p], stopPosition [p], Mathf.SmoothStep (0.0f, 1.0f, t));
             yield return null;
         }
     }
 }