There doesn't have to be more to the story. I work on cars all the time putting stereos and alarms and the such in. Many GM vehicles after about 2001 use "chips" in their keys to keep you from starting that vehicle without the correct key. When you put a remote start in a vehicle like this you usually need a secondary key to mount in the vehicle somewhere so that the "key sense" can read that you have the correct key in the car and trick the vehicle into starting without it in the ignition...now that I have stated all of this...I have seen a few GM's that I could turn the key to the start position and start the vehicle, while it is running I could pull directly out on the key without turning it and the key would come out but the vehicle would still stay running and could be driven like normal. The key tumbler is bad or the key is worn out.