It is very simple: there are 3 types of stories you can choose from:
1. the distraction story that was told by magicians (Kolin Burges + twobit idiot + irc chats + others): then depending on your preference you believe that Mark is either a ruthless swindler-criminal or an incompetent manager-dreamer
2. the MtGox story that portrays the exchange as a prey to a hacker who stole 6% of all bitcoins in maximum of 6 days without leaving any spikes in Bitcoin network activity
3. daddy Loozik's story that at least 50% of Gox's assets were gone before the alledged theft happened and that Gox's bankruptcy had been planned ahead (with distraction stories being its element)
How can I know if all is lost
of course by your own deductions...its the only consequense left.-.-......you know it by the selling at Gox !