When you opened the freezer door and the refrigerator door, you allowed the air to circulate from the freezer to the refrigerator through the vents. Once you closed the freezer door, the blocked return vents stops the air flow. That's a definite sign of a frozen return vent behind the evaporator coil in the freezer. You need to pull out the "false" wall inside the freezer and lift up the evaporator to expose the return air vents just behind it. Use your steamer to clean out all the of the ice build up. The reason for the ice build up is because the refrigerator door was left open partially for a period of time and caused a severe ice buildup inside the evaporator area. If you don't want to pull this apart, you can pull the plug and leave the freezer drawer open for 48 hours. That should give it enough time to melt the ice build up inside the evaporator.