Of course it was an accident. I saw CMDR Redacted and his friends having a wide range of accidents once. Very accident-prone group, they are.
In 2.4, bounties for murdering commanders always equal (or exceed) the murder bounty
plus the rebuy of the ship used to commit the murder, specifically to stop people switching to a cheap ship to die in, and therefore avoiding at no cost having a 7-day bounty on their head.
In 3.0 it will work somewhat differently - you would have got a noticeably larger bounty on your ship in the first place, but would have been able to clear it for less than 45 million (but more than the existing suicidewindering) at an Interstellar Factor, available in all good low security systems. They also are making NPC and Player bounties mechanically identical again, which means you won't get a nasty surprise about how the system works on your first player kill.