I feel I must alologise for the series of enormous nuclear explosions that have so damaged your planet. It wasn't me that caused them, and I really did do the best I could with the time and information I was given, but in this case, that wasn't good enough, and I am sorry for that. I am especially sorry because this business wasn't about you - it was between the bad guys and me. They hurt you because they knew I can't stand seeing innocent citizens suffer - and so it was only because I care about your people that you got blown up.
Even though, as I said, I didn't make the explosions happen, I know you hold me responsible for this accident. It wasn't my fault and I did try really hard to stop it - but my name is remains defaced, just as many of you are with raditation poisoning, and I know I must prove my innocense to you and to the galaxy, so that all the citizens can sleep easy knowing that I was the good guy all along. I only know one way to do this - I will catch the bad people that did this and bring them to justice. And then they will apologise for what they have done, and probably be punished too.
Remember this always - you have the consolation that your fellows died not in some bizarre accident, but as heroes - casualties of that great war between the good guys and the bad guys. And they were on the side of the good guys.
P.S. Your people will rise like a phoenix from the ashes - and when you do get around to rebuilding your civilisation, it might be a good idea to use a safer and more reliable energy source, as a mark of respect.