I doubt they're looking to break from the deal. This is more them taking a more assertive stance now that they know the Liberals have a ton to lose, since that gives them more leverage. I fully expect the Liberals will propose a new version that meets the NDPs criteria.

If they don't, that's basically Trudeau's fuckup, because they have the votes, everyone savvy knows this has very few policy downsides, and the NDP is open to whatever gradual rollout they need to make it practical.