[folivier]

Valve for entry door is in cabinet under kitchen counter next to door. Turn that valve and door should release trapped air and you can push it open. You can lock the door from the outside using the 2 key holes. But Tom said that to make sure you unlock the 2 locks before you restore air to the coach. So just leave the valve closed until that is fixed.
Sounds like you have an air leak and probably what you heard. Coach is probably unlevel?
Stay warm!