Deleted Frame, never closed iMovie, nor finalized, but cannot get it back....

Question

Help!!
My wife was editing a project on iMove '11, and deleted the last frame, which was a picture, rolling credits and music, along with a dozen or so other frames, beginning with this, the last frame, and working back towards the beginning.  She never closed the program, not finalized anything, but when doing control Z to undo each detetion, they all came back, with the excepion of the very first one deleted, which would have been the last frame of the imovie project.
How can we get that back?
We have not closed iMovie, not done anything overtly to finalize the project.
Please advise as to how to recover the rest of the movie, or if there is some way to quit the whole thing, such that it will revert back to the unedited complete version.
Thank you!!

Answer 1

I realize that, however, that would not solve, nor explain the fault found with iMovie, and would require one to basically keep an external drive attached to my macbook pro 24/7, while doing continuous and instan time machine backups.  There are many easier ways to prepare oneself in advance of these issues happening, which would be much less cumbersome than the above, however, my post was not about this, but about the functionality, or lac thereof, of iMovie, in this situation, and my attempt to see if I was missing some other avenue to recover (or undo) these changes.
Clearly, had I made a copy of the project, and then worked with the copy, this issue would not have been anything more thn a minor inconvenience, so it's really our "fault" for being in this situation.
What troubles me more than our own foolishness is Apple's continued stance that their products, be it hardware or software, never fail, and never have issues or bugs.  And that whatever is found on the internet, no matter how prevelant, is BS, most likely a "conspiracy" by some nefarious folks looking to sully the good name of Apple, and even more amazng is that none of the sr. technical advisors have "never heard of this", so I guess Apple must filter out anything negative on the internet, nor let them view these very forums.
As are seemingly most photo and movie professionals I work with in California, I am so fed up with Apple that I am looking at going back to PC based systems, and Microsoft based software, to process our workflow.  Apple has clearly thrown the professionals under the bus, at least in my opinion.
If anyone else has anything to offer, other than to use a back up copy of the project, in order to allow us to recover the deleted frame, I would appreciate it.  In the intermin, we will simply have to recreate it.
Thank you to all who take the time to read and attempt to help us.
And good luck in all your Apple related endeavors.....I hope your such problems are few and far between!