"FCP XML" sounds like the Final Cut Pro format, but your two lines example is not at all how that should be. I don't know if that is some official format, and even less which format it is.
But you say somebody converted it from FCPXML(?) I think you should try to get the 'untouched' FCPXML file (untouched, without any conversion) and load that into Subtitle Edit. You can then save it as SRT file.