Complex sentence: The contestant must stop the machine before it runs out of the assigned money in it, referred to as a lock out, if a lock out happens on a machine the contestant will receive a zero for the machine and must move on.
Split into simpler sentences: The contestant must stop the machine before it runs out of the assigned money in it, referred to as a lock out. If a lock out happens on a machine, the contestant will receive nothing for the machine and must move on.