After serious thinking Andrew wrote :
That would worry me.

Can you still completely shut off the kitchen from the rest of
the house ?. If so I would make an effort to keep that door
shut at night.

I could close the kitchen door, but I don't because I have two dogs who
may need access to their water in the kitchen. I have smoke detectors
in the hall, landing and the enclosed loft - all linked, so if one is
triggered, they all sound.

A smoke detector at the bottom of the stairs (plus elsewhere)
will warn you the moment any smoke starts to come up the stairs,
but tbh, the best escape route is down an enclosed staircase
and straight out of the front door, especially when you are
no longer 'agile'.

I am still pretty agile.