I do not see the issue either. Beta builds are placed in a folder of its own, to see if the features and fixes actually works. RC acts like a normal patch, overwriting existing files, however it is not compatible with any other version other then the previous stable patch. If that's stable, it would be release as the next stable patch.
If you can't make a backup, or simply won't, then don't use RC. It's not needed for anything else but testing. You still have the option of beta builds, which comes with the same fixes - though at times lacks a few features from RC.
Nothing you could wait on, though.
On the bright side, RC means that a stable patch is close. Dibs on early next week