You can use relation and query columns to get other tables data in your screen. You can also use a custom collection container et select another source for that component!
Create a custom collection container with a filter condition of the specific row you want, then put the big number inside that custom collection. To be even safer, add a limit = 1.
To answer this question specifically, yes each screen is normally connected to a specific row in it’s source table. If you don’t have any filters specified for the screen, and haven’t navigated to that screen from a collection, then it will most likely connect to the first row by default.