It's like someone is working down a list.
First scare the people to death so they'll vote the way you want
Second scare the party to death so they stop the Tory Brexiters from rubbishing the first scare.
How could you believe anything they say? Which is more damaging than what the Tory Brexit rebels are saying.
If the case were that clear to stay, then none of this fear and uncertainty would be necessary and if it is not that clear then tell us why we want to stay; not why we fear to leave.