Correct, a six auto fails.
The power reads: (at least as I have seen it described)
24" range. Draw a straight line. Any model touched by this line must pass a Intv test or be removed from the table. MCs get a -1 to the roll.
Things that could effect the ruling:
If it reads insta death rather than remove from the table.
If it is a shooting attack, meaning possible cover save.
I am definitely looking forward to getting my hands on this book.