Mathman,  I read your account of your accident and your thoughts contributing it to spiritual warfare and the possibility that your guardian angle was needed elsewhere or otherwise distracted with things in the heavens. 
 
I am sorry to say this but your account amazed me.  The Lord used the accident to re awaken a backslidden Christian to his need for a personal relationship with his Father, a prodigal son story.....and you believe that your angel was not diligient in keeping you from being this messenger of Gods mercy and grace?   Isn't the story more of God allowing more  events to happen to advance his kingdom using those who have dedicated their lives to him so that their vehicles, their time, their money, their concerns are all motivated in bringing those who have entered the promise of the Kingdom of Heaven (have become spiritually alive and are now partakers of the promise)  to maturity. 
 
God is waiting for those who are destined to qualify for positions in heaven to show their maturity, their faith, their devotion.....and we will not be gone one second before that work is done.  Rejoice in God using you rather than giving homage to Satan's realm for those things that happen in your life.