Bjorn,

I understand a certain green safelight is "safe" for a brief period after film development is half complete and would suppose something similar happens with your unsafe procedure. Those of us who learned "down and dirty" darkroom--rushed deadlines, portable darkrooms in hotels on a shoot, etc, etc. would turn on the lights after the film had been in the fix for a short time--but never before.

You may be very lucky; or everything I thought I knew (and which was taught me by cigar-chomping old pros, some of whom went back to the glass plate era) during the last fifty years or so is wrong.