Oops. Another engineer hits the contractor lists.
When I first started freelancing (mid 1980s) on my first day I inadvertently zapped 50k of source code. Now back then 50k of sourcecode usually equated to a working system. It was on a network drive and there was all sorts of work going on which meant that there was no way of getting it back.
I was allowed to believe that there was no backup for 10 minutes....
It was the start of a good relationship; I still do contracts for the organisation concerned to this day. But by 'eck, it were a long 10 minutes.