I think Bercow will have to allow MV3 - it's encoded in the motion that passed yesterday. This from the Guardian at lunchtime Thursday 14th, i.e. before the results were decided:

> Parliament will vote on a motion that sets next Wednesday as the deadline for MPs to pass a Brexit deal. If a deal is passed by then, the government will seek an extension of article 50 until 30 June. But if the deal is not passed by then, the government will need a longer extension, requiring the UK to take part in European elections.

The European Council is meeting on the 21st. So there won't even be time for a MV4. I think that's why Bercow was being so cagey in his wording.

Interesting times...