Sentry Mode events captured on video are saved, not deleted unless you manually delete the video recording. Eventually you might fill up the 1TB SSD, then you would not be able to save any more video to the drive without first deleting some of the files or reformatting the drive.
There is no way to continuously record and save all Sentry Mode video. Sentry Mode video is only saved when an event triggers the Tesla vehicle to save the most recent 10 minutes of video.
Honking will save the Dashcam video buffer. I suppose you could sit in the Tesla vehicle and honk the horn every 10 minutes or so. Might get old.