How can I mute a section of audio in iMovie?

I am working on a project in iMovie. I would like to mute a couple of seconds of audio inside one clip. I don't want to mute the whole clip. I have already carefully trimmed the start of the clip, and I don't want to do anything that is going to change that trim. Is there any way within iMovie of selecting a section of audio and reducing the volume of it?

If I have to, I guess I could redo the trim.

I could also detach the audio, export it, then work on it in Audacity and bring it back in. But this seems like a pretty basic capability.

But maybe it's only possible to adjust audio of entire clips.