Negative polar particles have generally been characterized as items for expressing disagreement or responding negatively to polar questions. What has been lacking in these accounts is attention to embodied activities. This paper studies the usage of the Estonian negative particle ei as a preface in realtime activities, showing that it halts the ongoing action, often for the sake of achieving intersubjective understanding and establishing epistemic authority. The paper shows how other matters besides logic and truth-conditions define the meaning of the negative particle. Analysis of linguistic function demands transgressing the boundaries of language and scrutiny of co-present interaction in its temporal emergence. The paper argues that several discourse functions of ei are also more accurately described from the vantage point of its usage in multimodal face-to-face settings than from the logical properties that the item happens to display in limited sequential contexts after yes/no interrogatives.