Is recording spotify without actually saving it onto disk legal?

[behenate]

Hi.

This question is kinda weird, so I apologize if I posted it into wrong section.

So, recently i had to sync MIDI with original music in Audacity. Since I had no mp3 file and i didn't want to download, because it is illegal, I came up with idea. What if I just record track into Audacity without saving the project (so it stays only in the RAM) until I sync MIDI with it. I think that's OK, because when you play song on spotify it is also loaded to RAM (buffering) and while i was working on MIDI in Audacity I just kept the recorded song repeating, but muted (so while recorded version was in my computer's RAM spotify version also was in RAM) . Is it even legal? I know it is really tricky, but I hope you get it.