Thanks for chiming in so quickly, @squid.
I have decided not to respond to hostile comments. I am less than willing to spend my free time on internet trolls.
To clear things up: as per https://github.com/rix1337/docker-ripper#do-you-offer-support I happily am able to confirm, I am not able to offer any support on this issue. Transparency is always important in open source projects - that's why that passage was added to the readme.
Ripper generally works well and anyone is free to solve issues and improve the project by sending a pull request.
@stayupthetree if you need further assistance and do not want to become a sponsor, then you can either:
a) ask others in the community how they managed to get multiple drives working
b) ship me a secondary optical drive for free (ideally your exact model) so I can try and diagnose this
Edit: To further facilitate transparency I have reworded the https://github.com/rix1337/docker-ripper/blob/master/README.md#how-do-i-rip-from-multiple-drives-simultaneously section in Ripper's readme.