User blog comment:Damous/Why Bioware has NOT betrayed us/@comment-3097746-20120313120439/@comment-227314-20120314021257

The only answer to the mass relays not destroying the systems they're in is that whatever choice u make, the energy required to transmit the signal for control/synthesis/destroy would take all of the energy of the mass relays, by doing this the catastrophic system destroying power inside the mass relays is released so it can no longer destroy an entire system and it can only destroy itself in the process.

At least that part makes sense, the last scene with joker on the normandy and everyone aboard it is the part that makes no sense, I could have lived and understood the ending perfectly without it. Shepard surviving at the end would just be a bonus