You bring an interesting question to the table, thanks for sharing! NFPA 99 2012 edition B.14.3 Suggested procedures for Hyperbaric Chamber Operator to Follow in Event of Fire in Class B Chambers does not provide the level of detail you are asking for. In my opinion what you are getting at is how many staff members does it take to handle a worst case event.
Staffing is addressed in 22.214.171.124 Rules and regulations, The number of chambers and type of treatments, the layout of the room, level of experiance and training all affect staffing. 126.96.36.199 Emergency Depressurization and Facility Evacuation Capability has value to this discussion as the requirement is for timed drills. It is important to work through drills as you are doing to discover how many staff, per chambers in use.
In the scene you provided; I would evacuate all chambers as fast as possible and would not hold the un involved chambers at pressure, rather get the patients out and evacuated to a place of safety
Stop the flow of oxygen to the chamber with the fire inside. Decompress the chamber as rapidly as possible, call the code (or 911, get help coming) have a fire extinguisher ready, remove the patient and evacuate, closing the zone valves as you leave the department...this does not preclude getting the un involved chambers out (as above) and agin I would not wait to do so. This list is not in a specific order each scenario may work out abit differently. There has been much discussion on whether to call for help firts in our department or respond to the fire. I would argue that with adequate stafing you can do both at the same time.
Yes we would be willing to share our procedure ( attached).