Audiobooks - Libby to MP3 via Audacity recording. Muting sound without closing book

I have been downloading library audiobooks to Audacity so I can transfer them to my MP3 player since Libby’s policy changed a couple of years ago. Usually, I set the book going, mute my speaker so I can work, and then retrieve the recording when it’s finished. Just today, however, the audiobook stops when I mute the speaker. Any way around this?

I just figured out a semi-fix. On the tool bar (as opposed to the “mute” button) I lower the volume until I can’t hear it. It still seems to record at normal volume on Audacity, however. Here’s hoping.