Get into a battle with multiple enemies and wait until your health is really low (i.e. 10 - 25).

Then activate Beserker just before you enter Fight For Your Life! Mode and kill one of the enemies to gain a second wind.

With the two powerups you should be able to run as fast as Brick in Beserker and you'll also be able to fire your weapons!

To cancel the cheat either activate Beserker again and end it, or if you die you will also lose it.