User blog comment:The Milkman/The Writing of the Ending/@comment-1341687-20120529185853/@comment-1341687-20120529201617

The rest of the fleet isn't affected because they aren't riding the relay at the time. Something that shouldn't have been done by the Normandy regardless. I was always under the impression that Joker wasn't just running, but that he had hopped into a mass relay and launched somewhere, that's why the beam is more narrowed, because it itself is also riding the relay to continue its "explosion mission". Which also explains how he could crash on a random jungle planet.

And yeah, to the second. I completely agree.