"Él no quiere que ellos cierren la puerta."
Why is the verb "to close" imperative here? Why wouldn't you just say "Él no quiere que ellos cierran la puerta."?
You might be tempted to think "because it hasn't happened yet", but that is exactly the reason for the subjunctive.
"Él no quiere que tú cierra la puerta."
The subjunctive form would be "cierres".