What you're describing is a transition failure, and it's one of the most underappreciated executive function challenges. When you were about to sweep, your brain had already built up complete mental and physical momentum for that specific task sequence. The moment you realized you needed the Swiffer upstairs, everything changed. You had to stop the current task flow, navigate to a different location, retrieve an object, and then return and re-initiate the original task. That's four separate executive function transitions, and each one is a potential derailment point. What looked like "sweep floor" suddenly became "manage a complex multi-step retrieval mission," and your brain's motivation system responded accordingly.
For future situations like this, one approach that can help is staging the task equipment, for instance keeping the tools you need in the spaces where you'll actually use them, even if that means keeping duplicates. It's all about reducing the number of transitions your brain has to manage. Another strategy is to try to catch yourself in that moment when you realize something is missing and make a conscious choice: either commit to the full retrieval mission as its own separate task, or give yourself permission to pivot to something else entirely without the guilt. Sometimes the kindest thing you can do is acknowledge that the activation energy needed to follow through just got too high and let yourself off the hook so you dont feel so guilty.