[UX] Users confused with "Retake" and "Keep scan" on refinement screen (shown after suboptimal scan result))

Users who only want to scan one File doesn't click on "Keep Scan (Scanning)" as a consequence they loose the document.

"Keep scan" is ambiguous it could mean:
a) Keep scanning to get more images
b) Keep this scan permanently

Steps to reproduce

1. Open the new iOS 1.3.2 App
2. Connect to demo.owncloud.org
3. List of Files and Folders showed
4. Users presses "+" right corner and clicks on "Scan document"
5. User scan a one document page
6. If the feature detects some quality deficiencies the screen will show "Retake" on the left corner and "Keep Scan" on the right corner on the scan document

Expected behaviour

Users expect "Save" button

Actual behaviour

Based on the user research, participants feel confused and don't know what to do to save their document.

Reference:
Video: Participant_SK
Min. 0:28
Video: Participant_HP
Min 2:44
Video: Participant_AB
Min 0:34
Video: Participant_FA
Min 8:12
(https://cloud.owncloud.com/index.php/f/5160419)

Reproduce the refinement screen in the iOS 1.3.2 scan flow using the listed steps, then trace how the Retake and Keep Scan actions handle a single-page document. Done means users can clearly save one document and understand which action continues scanning versus keeping the current scan.