Don't add an elbow to the city water connection

Took a previous forum's suggestion and added the elbow. Worked good for several campings but on this last one I removed the hose but FORGOT to remove the elbow. BIG MISTAKE!. When I arrived home, I opened the shells and observed the damage. A torn Bathroom window screen, damage to the metal window frame, and a serious 10"gouge line down the aluminum inner wall below the window frame. This is in addition to also breakiing the plastic housing that holds the water connector! Don't Do It!