First you must take time bomb from the magic box and if you take time bomb buy galvaknuckles and go to the bank.
Next take your money from the bank and plant your time bomb.
Then go behind the cupboard of the bank,prone and electroshock the keys.
Now wait some seconds for the money go into the thing like ($).
And then explode the time bomb and you see you have again your money and the ($) is again here.
Then take it and you have double money.