While it’s none of my business, have you thought of covering the A350 and sunrise operations by a side letter to the new EBA? Then you and the company could agree to your latest EBA and to study the health effects of sunrise together and agree to negotiate something later.
You could even spell out the issues to be negotiated, the time frame and the parameters.... Words such as “will not be less than ...” come to mind.
That removes the brinkmanship and sets up for good faith bargaining by removing uncertainty fear and doubt.
‘’Then you both may get a win/win.