Reinstalling Xbox One game from disk, when I installed it on external drive, and have "misplaced" that drive?

Yesterday I brought my Xbox One to a friend intending to show him the platform, the games, the graphics, features, etc.

However, I had forgot to bring the external drive. In my haste when unplugging everything at home, the disk was left behind.

Unfortunately I had installed all my games on that disk.

However, I had brought the Battlefield 4 disk, as it was already inserted into the console before I took it with me.

However, reinstalling from the disk didn't seem to be an option, nor to uninstall it. The only option I had was to install it from the store, which started a 45GB download which took all night.

In the above scenario, is it possible, and I just didn't find out how, to do the following:

1. Uninstall the game, or make the Xbox forget that it was installed on the external disk, preparing for a new disk-install?
2. Reinstall from the disk, and not only from the store/download?

For instance, what if the disk was lost, or destroyed, or otherwise permanently gone, what would I do then, would my disks be worthless?

OK, since it seems nobody else has experienced this or not quite being able to understand what I'm seeing, I did this:

1. Turned off the Xbox One
2. Unplugged the external drive
3. Turned on the Xbox One

As before, the Battlefield 4 disk is in the console.

On the home screen I can see the disc tile lower right, showing Battlefield 4. If I use the controller to activate it, the BF4 screen goes fullscreen briefly, and then returns to the home screen with a gray error message that says the following (verbatim):

For {0}, connect your external storage
If you have the storage device or the disc, use that. Otherwise, install Battlefield 4 from the Xbox Store. (0x87e000c8)
[See in Xbox Store] [Cancel]

If I activate "See in Xbox Store", it goes to the store item for BF4, where I can Install/Pin to Home/Rate. Activating Install installs the game, but from the online store. This takes a lot of time.

If I return to the home screen, navigate to the disc tile (again) and hit the menu button on the controller, I have these choices:

• Go to full screen
• Pin to Home
• View game details
• Manage game

If I use "View game details", again I end up in the store. If I use "Manage game", I get to a gray screen, with the BF4 icon on it, and an option on top of the big icon to install it. Activating that informs it it'll take a while. When accepting that, it is queued up, 35.3GB. None of this spins up the disk, and it is a slow install, so it is being installed over the internet.

OK, so that didn't work, let's see what I see under storage management.

-- and now I found the solution, I will add my own answer here.