in a previous post i talk about how hackable physics might allow a superintelligence to take over very quickly (perhaps faster than celerity).
in psi rewriting i propose that multiversehood can be more cleanly described as a particularly implemented feature of the cosmos, rather than an intrinsic thing.
but, if the cohabitation of multiple timelines is indeed an implemented feature rather than a primitive one, then there is a possibility that it is hackable, and that a superintelligence could hack across timelines.
now, it is to be noted that even if hackability exists, it might still be limited: perhaps there something like a light cone at play, or perhaps a given timeline can only access a finite number of other timelines.
it is to be remembered that timelines are not slots, they're not variables that hold values; timelines are the values themselves. still, hackability could mean some branches of the causality graph stop getting computed, for example.