but I did find it kind of funny that less than a year after the accident Sarah was already a psycho assassin.
There was zero evidence of this.
She certainly turned evil fairly quickly.
Also, no evidence of this either.
So (once again) you jump to conclusions based on nothing but your silly assumptions.
So far we have seen that Sarah arrived on the boat, was brutalized, and then Ivo's intention was to use her in some kind of experiment.
When she next appears, Ollie is on the freighter, she is acting without affect, kicks him around and is holding a knife.
The connotation is that she is going to give him some more of those scars that everyone asks about.
It appears that in the time frame between the Queen's Gambit sinking and her kicking Ollie on the freighter, she has been tortured to the point of becoming a torturer.
This may not end up being true, but all points made so far lead to this conclusion, and there is no evidence of another situation.