At the right edge of the Preform screen you have a scroll bar that you can use to scroll through the slices.
Or you can use Page Up, Page Down, Home and End keys to do the same.
I just had a failed print myself and upon examining the suspected area I found this strange slice.
That triangular area that only exist in this single slice I’m pretty sure did dangle around or fall of and block the laser for the rest of the print.
