An idea for the best possible Mind Backup shortcut

Perhaps memory data extraction tests should first try to record all of a subject's secrets.
Suppose you wanted to reconstruct the mind of someone you knew. To feel authentic to itself, that reconstruction would need to know all the things they would never reveal or talk about to others.
Maybe these secrets aren't needed to act authentic enough to seem real to others (at least for a while), but secret hang-ups determine personal interests and motivation.
Otherwise, a Mind Backup is really a simulacrum of someone's memories of a dead person, not of the person's own memories. These memories definitely include all their traumas. They may be the reason people's reactions can never be fully predicted.

In an interesting aside, Scientology is also very interested in the deep dark secrets of its parishioners. It keeps these secrets for them to form an ever tightening bond.