I'm trying an offline install with DVD media.
When an offline install gets to the stage where it is copying the install media's package list(s) to the target computer - just before package selection - and the user needs to change shuffle the DVD, the DVD drive door is still locked and won't open.
You have to answer"yes" to the first scan and let it fail in order to unlock the DVD drive.
It then "forgets" the first DVD and keeps prompting you for it at the end of that stage of the install.