"Systems preserve the decisions they cannot revisit.
In a data pipeline change where failures can be silent, everyone wants to keep options open. Options are expensive when they prevent commitment.
Uncertainty is not the enemy; implicitness is. You see it in a local optimization that creates global instability, where a missing boundary becomes a permission slip for everyone to improvise. If you do not name the cost now, it will return later as rework, pager load, or a standard nobody can enforce. The system learns from what you allow under pressure, not from what you say you value in calm weeks.
Name the signal that ends the attempt and the action you will take when it appears. That is what makes execution calmer. Stop while it is still simple.