Thank you for your question and I understand your concern. Based on the fault code "F21", the washer is not able to drain any water or not draining fast enough.
If the washer is not able to drain water, the door will not unlock. There is an emergency door release tab/pull ring attached to the bottom of the door lock assembly.
The lower access panel can be taken off by removing the screws and then reaching up under the door lock and pulling downwards on the pull ring. Pull down and then you can open the door. Note: Using the wrong kind of detergent or using too much can cause F21 to display and then "SD" for suds to display. The drain pump cannot pump out suds and the suds can cause the pressure switch to take a long time to reset. High Efficiency (HE) detergents are recommended for front loading washers otherwise it can cause F21 or SD to appear.
If the washer is new and under warranty, I strongly suggest calling and setting up a service appointment to have your washer repaired.
If the washer is draining water and F21 continues to display, the water level pressure switch is likely faulty and will need to be replaced.
I recommend draining the tub and then the drain pump filter should be checked and cleaned.
Possible Causes/Procedure for a "F21" fault code:
Check the drain hose and make sure it is not plugged or kinked.
Unplug washer or disconnect power
. See images below.
Check the electrical connections at the pump and make sure the pump is running.
Check the drain pump filter for foreign objects.
Plug in washer or reconnect power.
If the above does not correct the problem, go to step 7.
Unplug washer or disconnect power.
Replace the pump.
If you do not feel confident repairing this problem yourself, then you can have it repaired at your home by a Sears technician. Here is a link for the website:
Sears Home Services