I feel slightly foolish asking this, as perhaps the answer is blindingly obvious and I just can't see it, but...
Is there an explicit command to unlock a door? In the scenario that a locked door is unlocked by an event or an NPC, not by the player having a key. I can work around it with a 'match (unlock door) ...goto' type thing, or perhaps make it a block_path and add a condition to it. But would be easier if I could just command the door to be unlocked.