Instant Loophole Tony never launched the bomb off the launch site so he only blew himself up all is well.
Actually no, you can detonate a bomb with out launching it. If the bomb was powerful enough to destroy the whole world it is then it is powerful enough to destroy the world just from the launch site.
Even if this isn't true that the bomb can't destroy the world from the launch site that means the bomb has been destroyed - killing the topic.
Bomb destroyed but the world intact - thread ends because bomb is destroyed
Bomb destroys world - everyone dies and thread ends.