The mutant has the ability to recover from injuries received in battle.
At the end of any turn during which the mutant has suffered one or more W, it may try to regenerate, even if it is 'dead'. Roll a D6; on a result of 4, 5, or 6, all lost W are recovered. If the regeneration roll is unsuccessful, the mutant loses the W in a normal manner and must heal as normal.
A mutant may regenerate W any number of times, so long as it continues to roll 4, 5, or 6 when testing for regeneration. It may even return from the dead several times during the course of the same battle.