Why the worry of temporal psychosis on Seven of Nine?

Question

In the Voyager episode Relativity, Seven of Nine is recruited from the past to help catch Captain Braxton, who is planting a temporal bomb to destroy Voyager.

But there's a catch: After 3 jumps, (to the future and from the past I believe?) she will start to suffer from temporal psychosis. Why is this a problem? It's clear that only the future Seven of Nine would suffer temporal psychosis. For example, only the "future" unranked Braxton was suffering from temporal psychosis, not the "current" Captain Braxton.

So why would there be a worry about Seven of Nine getting temporal psychosis? If the past Seven of Nine dies, can't they recruit a new one each time?

Doesn't it just wipe the slate clean and they can have 3 more jumps with a new Seven of Nine?

Answer 1

First of all, allowing someone to suffer from any malady or allowing them to die just because they can always "recruit a new one each time" seems a bit uncaring, and not at all Starfleet's modus operandi.

Also, the episode makes several references to "reintegrating" the two versions of both Braxton and Seven of Nine:

JANEWAY: Wait a minute, let me get this straight. I'm going back in time to stop Braxton, but you already have him.
DUCANE: And there's a third one in our brig. I arrested him earlier today. But, don't worry, they'll all be reintegrated in time for the trial.

DUCANE (To Seven of Nine): You'll both be returned to your time frame. You'll be reintegrated with the other Seven of Nine. Since none of your time jumps were to your foreseeable future, only the past, I see no reason to resequence your memory engrams. But remember the Temporal Prime Directive. Discuss your experiences with no one.

Since this "reintegration" process is never really explained, ("I hate temporal mechanics!") it isn't clear what would happen to Seven of Nine if her past self is not reintegrated with her present self. Might be nasty.

Answer 2

Recall that Seven was already suffering from sensory aphasia before Relativity recruited her a third time, at which point they warned her those symptoms would be a side effect of a third jump. Evidently they cannot "wipe the slate clean," since Seven was already becoming ill because of a time jump she had yet to take, suggesting there is some nonlinear element to human physiology related to consciousness that is affected by time-jumping.