Boot in single user mode despite rEFIt in Mac OSX.

When you have rEFIt installed and you apply the shortcut to boot in single user mode (S), you actually land in the EFI shell.
In order to avoid that, boot as usual.
Then choose the Apple icon and press F2.
You will be presented with a series of alternate options to boot Mac OSX ( e.g: single user mode, verbose mode, etc.)