The title is inaccurate no matter what is going on with MtGox, because if anything, MtGox is insolvent, not bankrupt.
Being on the run, i.e. living in fear, is not fun. Not even for an anonymous darknet marketplace admin would it be fun, when the chances of being found are minimal. For Karpeles, if indeed MtGox is insolvent due to theft, it makes more sense to be honest about what happened and declare bankruptcy.
Man, how do you accidentally lose three-quarter million bitcoins and not notice. It's like sleeping through Hiroshima and not noticing anything different when you wake up.
If you're a cockroach...