Yeah, I think either setup would have a scenario that doesn’t reset the Sim Door to Off depending on if the door is closed within the first 30 seconds or not. (If it the door is closed after 30 seconds, your rule won’t reset Sim Door; if the door is closed within the first 30 seconds, my rule won’t reset Sim Door.)
If the door is closed after 30 seconds is not a concern for you, then your rule may fit better. Otherwise, you may combine two to cover both scenarios.
The other alternative is to replace the Door closed trigger in my rule with Door stays closed for 31 seconds (to be larger than the 30 seconds window), so Sim Door will always be reset to off 31 seconds after the last door closed event.
See the Context Variable release announcement and rule examples below. 