Ctrl-A/Ctrl-C then paste Ctrl-V in the editor will save everything that's visible.
Probably need to create a parallel automagic saving operation that periodically closes the open file and then appends new to avoid the possible catastrophic loss going forward...
diary only toggles the state of saving; it doesn't do anything with that already gone by and displayed. BTW, note that you use the up-arrow key to recall all lines, irregardless of how many are visible owing to the buffer number of lines preference setting.
