Your assumption is that given a certain set of conditions, only one result is possible. Quantum mechanics suggest that there can be multiple possible results given the same conditions.

Actually there are infinite results possible and since there is also an infinite number of parallel worlds, all of them will be played out. However what I've written above is in relation to the one world that our mind can perceive at any given point of time.

Also, if we are going to get metaphysical here, it could be argued that a person's "soul" or "mind" could actually be the final determining factor on which outcome actually takes place.

The mind will indeed determine the outcome, however the mind is reactive to stimuli - meaning that if I tell someone "don't think of a black cat" they will think of a black cat.

The minds reactivity renders it a re-active force / a gear which is moved by other gears. Naturally, our concept of free will goes down the drain.

The "soul" is in another layer of reality which is beyond this realms causality and chain-events/chain-sequences. In general, this world is mechanical / mechanistic in its operation except a few "islands". One of these islands is the "soul" - which is another way of saying, our self beyond this virtual reality-simulation. The man behind the keyboard (spirit self), instead of the avatar inside the game (human self).

All choices originating from the non-mechanized aspect, that break physical causality and mind-reactivity, introducing "anomalies" into the predictable equations of the mechanized world, are always implementing a God-type perspective anyway, so there would be no "accountability" in the negative sense because the wisdom involved is already God-like (the soul has access to non-linear time and its wisdom is for all intents and purposes infinite in comparison to typical human understanding).