Worst case behavior for updates using SQLite PRAGMA synchronous = OFF and journal_mode = MEMORY in iOS

By using both the synchronous=OFF and journal_mode=MEMORY options, I am able to reduce the speed of updates from 15 ms to around 2 ms which is a major performance improvement. These updates happen one at a time, so many other optimizations (like using transactions about a bunch of them) are not applicable.

According to the SQLite documentation, the DB can go 'corrupt' in the worst case if there is a power outage of some type. However, is not the worst thing that can happen is for the data to be lost, or possibly part of a transaction to be lost (which I guess is a form of corruption). Is it really possible for arbitrary corruption to occur with either of these options? If so, why?

I am not using any transactions, so partially written data from transactions is not a concern, and I can handle loosing data once in a blue moon. But if 'corruption' means that all the data in the DB can be randomly changed in an unpredictable way, that would be a strong reason to not use these options.

Does any one know what the real worst-case behavior would be on iOS?