Good question. Close quarters with poor circulation would be a concern if someone was in the sick bay area. I think there was a Nat Geo prepper show that had a similar situation where the guy duct taped a air tube that inflated when he turned on some type of air blower (think of those used for home water damage). For biological warefare, I would use some type of NATO threaded tubes going outside but pointing in different directions for wind current so that you get all sides of the wind blowing and put some gas mask filters on them (Although some will say that gas mask filters only last x number of minutes/hours) you might want to research this.