she ingested some sort of meal around 2 hours before she died..
its a hot summer night. she would be highly unlikely to have food stored in a hot bedroom where the aircon is broken.. so . she has to go downstairs to the kitchen, and to the fridge.. carefully unlocking the bedroom door on the way out, .. uses the toilet DOWNSTAIRS, and then comes back up, unlocks the bedroom door, closes it, locks it behind her..
this careful locking and unlocking of the bedroom door is feasible, because that's what Oscar does. He says he does that. That's his story. I'd imagine he'd insist everyone in his bedroom does the same should they wish to roam around the house gathering a snack. And I would think Reeva would follow his preference in his house .
the toilet she was murdered in isn't the only toilet in the house. in fact , the 2nd bedroom has an ensuite toilet as well.