During the "Heroes in Crisis" story arc, Wally was initially believed to be one of the massacre's highest profile victims at the superhero rehabilitation facility known as Sanctuary, but is later revealed to be not only alive but actually the real culprit of the murderers. Wally explains all in his confession, one of the many recorded video transcripts that Wally himself sent to Lois Lane, while identifying himself as "The Puddler", that he's felt "alone" since his return, as his family remains wiped from existence, with no one even to remember them, except him. These tortured memories are what led him to Sanctuary in the first place, but he found no comfort there, instead, he relates how he still felt alone because he didn't see the same kind of pain in its other residents, and the program's anonymity only compounded his feelings of isolation. Wally therefore did some digging of his own into Sanctuary's resident records and uncovered a truth that he had been denying. Every one of the heroes at Sanctuary were in fact coping and trying to overcome their own personal traumas, just as Wally was. Uncovering all this information at superspeed led to a flood of emotional experiences that momentarily allowed Wally to understand he wasn't so alone after all. While this realization might have initially given Wally some comfort, it all came to him in a comparative instant. Instead of helping to heal him, the onslaught of emotions broke him. In turn, he momentarily lost control of the powers of the Speed Force contained within him and in another fateful instant, the powers of the Speed Force were unleashed on the other heroes within Sanctuary, killing them instantly.