This city is in a state of anarchy. The only thing to do is to abscond. Survival is arduous. Life is daunting. Those still alive have to be intrepid. The world is on the precipice of destruction.
But I have a chance to rectify these problems and I'm fated to succeed. I have to commit larceny and get picked up by the very corrupt and pompous police who will revile me with their big words and will then try to incinerate me. I will then switch their government entrance card with another fake card to reprieve him and to gain access to the Power Tower, where the prototype for the first time travel machine is being held and where the first biogun is. This gun makes living things inanimate, and pliant enough to fold.
By then the policeman will figure out he was hoodwinked but hopefully, by that time I'll be in the past disentangling all of this worlds problems and making sure this never has to happen again.
It's done, the past is fixed and the future is saved.