This paper investigates a pervasive phenomenon in video-mediated interaction (VMI), namely, simultaneous start-ups, which happen when two speakers produce a turn beginning in overlap. Based on the theoretical and methodological tenets of conversation analysis and interactional linguistics, the present study offers a multimodal and sequential account of how simultaneous start-ups are oriented to and solved in the context of English as an additional language (L2) tutoring. The micro- and sequential analysis of ten hours of screen-recorded video-mediated data from tutoring sessions between an experienced tutor and an advanced-level tutee reveals that the typical overlap resolution trajectory results in the tutor withdrawing from the interactional floor. The same analysis uncovered a range of resources, such as lip pressing and the verbal utterance ‘go ahead’, employed in what we call enhanced explicitness, through which the withdrawal is done. The orchestration of these resources allows the tutor to exploit the specific features of the medium to resolve simultaneous start-ups while also supporting the continuation of student talk. We maintain that this practice is used in the service of securing the learner’s interactional space, and consequently in fostering the use of the language being learned. The results of the study help advance current understandings of L2 instructors’ specialized work of managing participation and creating learning opportunities. Being one of the first studies to detail the practices involved in overlap resolution in the micro-context of simultaneous talk on Zoom-based L2 instruction, this study also makes a significant contribution to research on video-mediated instruction and video-mediated interaction more generally.