You only need it to be cancelled if the door is open, so you could put it inside the IF THEN. That being said, even before (first action in your rule) would be fine since in the other case there either wouldn't be a delay scheduled (so it would do nothing) or the door would already be closed (so you don't need to cancel it and, again, sending a close() to a closed door shouldn't actually do anything). You can see lots of examples in the Rule docs, which I'd strongly recommend reading if you use Rule Machine (these are technically a bit outdated, written for Rule 4.x and assuming some Rule 3.x knowledge, but Rule 5.0 isn't that drastic of a change so most still applies): [Released] Rule 4.0. Note the examples of cancelable delays towards the beginning of the doc.
Or...you could use the "Wait" actions we've suggested above instead. 
Note that these generally work best with a specific trigger, not a "changed" trigger, due to how their automatic cancellation works--but it makes things easier since you don't need to do it on your own. But either (wait or delay) should work if you put the right pieces together!
