A second referendum is Theresa May’s only possible get out clause if she can’t get her deal through, won’t go against the manifesto for soft Brexit and won’t rescind article 50. So if parliament tries everything and still can’t find a way the only option left on the table is a second referendum. Keep up 😉
And yeah a general election is another option too but with both the tories and labour up shit creek in terms of how they’d possibly draw up their manifestos that’s perhaps best done at a later stage