In accidents where significant numbers of passengers have died
The problem with quoting historical accidents that occurred decades ago is that the world and technology has moved on since.
(a) The risk of actually being involved in such an accident is very small indeed.
(b) A large number of safety related enhancements have occurred that were not in place all those years ago.
Even if you do sit in the back next to the toilets, there remains the very real possibility of you suffering significant injuries as a result of lap belts and forward facing seats than there is of you sitting in seats further forward.