Apparently everyone in the world is Googling this right now because the MN state website explaining what it is is down.
Finally got through.
So third degree murder basically is manslaughter but with the addition of acting in a dangerous manner. He faces up to 25 years in prison for that alone.(a) Whoever, without intent to effect the death of any person, causes the death of another by perpetrating an act eminently dangerous to others and evincing a depraved mind, without regard for human life, is guilty of murder in the third degree and may be sentenced to imprisonment for not more than 25 years.