I recently had a "working" copy of my Lynx1 Spare Parts List made.
Last night I was browsing through it and saw the following on page 39-7:
C19SR 110353 Emergency door lock key 2
This does not move the key discussion forward much but it does confirm that two keys were issued with each vehicle. Maybe the trapped occupants opened one of the vision hatches and handed the key out to their rescuers!
Alastair
F60S
Lynx I MkIII*