How to align git working copy using only Android Studio git plugin GUI

There are a bunch of decade-old answers for using git command line to accomplish various goals, but this question is how to use the standard git plugin for Android Studio 3.3.1, GUI only to "fix" a common "problem". Maybe it's "impossible" without git command line. If so, then that's the answer: "impossible", but you would have to wonder about the authors of the VSC plug-in.

Scenario

You would like to test some code that's hosted on github.com and you only want to use the GUI of Android Studio. You're asked to test but don't know how to switch branches and keep an exact match with the code you're supposed to be testing. You have read-only access to the remotes.

Checkout / Clone

Within Android Studio, you select VCS > Checkout from Version Control > Git, then you paste the url you found while using your web browser. So it might be something like https://github.com/someguy42/someproggy42. You hit the test button and it says Connection successful. Then you hit the Clone button.

You check the remotes: VCS > Git > Remotes... If the one you want isn't there, you do(plus sign) > (url of repository found in github.com). You specify the name of this remote as someguy42.

You then do a fetch VCS > Git > Fetch. At the bottom right of the Android studio, you click and you see someguy42\master, someguy42\feature1, someguy42\feature2.

All is well. So far.

Testing Two Branches

You are asked to test both features.

So from the list you see by left clicking on the bottom right of the IDE, you right click on someguy42\feature1 > Checkout As... > feature1.

You complete your work on feature 1.

Now it's time for feature 2, so you repeat the process as before: from list on the bottom right of the IDE, you right click on someguy42\feature2 > Checkout As... > feature2.

You notice something odd. You now have a mixture of feature1 and feature2 in your IDE!

You prove this to yourself by going to the Android app folder, right click and select Git > Compare with Branch... and you compare with the remote someguy42\master. You expect to see only files changed in feature2, but both feature1 and feature2 files are in the list.

Question

What steps, executed exclusively through the Android Studio GUI and the VCS plug-in, would make it so your working copy was a guaranteed pristine copy of only files from feature2?