Simplicity
As soon as the men have passed and seem out of earshot. You slowly crawl out of the opening. When you turn back to look at it, it seems like some sort of vent. The air blowing out seems salty and sea-like. That opens up a possibility that you are on an island of some sort, one that harbors a prison. You examine the key around your neck further, you see that the designs on it match the one on the knob of the door the other men were. Just as you decide to open the door with the key, the woman with the voice you recognize cries out again, in pain. With the ventilation tunnels all around it seems to come from everywhere at once. But if you focus you pinpoint it to the vent that breezes the salty air. Do you make an attempt to find the woman or try to open the door with the key.