I'm not sure what you mean by "Video Quiz". With the Canvas quiz tool in general, as long as the time limit has not expired, the availability dates have not passed, and the quiz has not been submitted, the student can come back to the quiz and resume where they left off. Questions should have autosaved as they were working on it the first time.
https://community.canvaslms.com/t5/Studio/How-do-I-create-a-Canvas-Studio-video-quiz-in-a-course/ta-... A video with questions throughout the video. Students that do not finish during class are having to watch the full video from the beginning when they get back in to finish the "quiz". Thank you,