Fire in accommodation starts gas oven (3,2)
I believe the answer is:
Here is my best explanation:
'fire' is the definition.
'accommodation starts gas oven' is the subsidiary indication.
'accommodation' becomes 'let' (I can't explain this - if you can you should believe this answer much more).
'starts' says to take the initial letters.
The first letters of 'gas oven' is 'go'.
'in' is the link.
(Other definitions for let go that I've seen before include "Discuss no further - dismiss - release", "Release or free", "Free", "Release grip", "Dismiss (from ones thoughts?)", "Set at liberty, loose grip on", "Release or permit to depart", "Loose one's grip", "sack" and "Give up".)