Hi alexis712
Only after exhausting Joseph_S's recommendations below! And only if these photos are that important I have another suggestion.
Stressing that this is a last resort. And also because it looks quite a small library as this method is quite labour intensive.
The suggestion being is to enter the library and pull out the photos manually to a temporary folder or on your desktop and then import them to your current working library.
To do this > right click on the library where the volume it is stored and select 'Show Package Contents'. All photos will be in the 'Masters' folder.
They will be first in 'Year' folders (year of uploading to library, not year taken). Then that will be split to month then day, etc.
If its only a few photos you need then it will be quite easy once you find them. If you want them all then it will be quite time consuming and you will need to be methodic drilling down to the picture/s to copy, then working back up.
Note - to copy hold ALT after selecting picture or group of pics, whilst holding ALT start dragging, a green cross should appear to show you are copying. If you just drag and drop it will move not copy the picture.
Of course if you are not bothered anymore about that library or conscious of space saving and don't want to duplicate, then the easiest way is to drag not copy the pictures to your chosen destination. This will leave the folder they are in empty. You can then click back one and delete the empty folder and keep repeating till you are back to the 'Masters' folder with no folders in it.
All pictures from that library will be in your chosen folder.
Pls also note this will only rescue the original pictures.
Titles, keywords, location or modifications will not be migrated. If you need/want these then you will have find a fix for the library. This might be as simple as each library is from a different version of Photos.
Hope this helps