Well the article says the DUP have to come up with an alternative if they want to invoke article 16. Unless they say the alternative is 'no deal' then I wouldn't expect that.
It's not surprising the DUP are upset by the way. During the May negotiations of which they were part they insisted they didn't want a border down the irish sea, yet that's what seems to have happened now that they aren't needed by the government. But I don't see any other way to do it unless you reinstate border checks along the border between NI and Ireland, which would be almost guaranteed to restart the 'troubles', and nobody wants that.