Easy. I know the party is going to be traveling through a forest for three days. So I roll random encounters for all three days prior to the session ever starting. I know what the random encounter will be, when during the day it happens, what direction it is coming from, and so on.
A day is a day. If they are in the forest, the random encounter is happening at 6pm that day, whether they are futzing around looking for herbs or traveling straight through. Random encounters are not preset encounters with a specific location, but rather a specific time. They wander into the group, which is why they are also called wandering monsters.
With regard to the cook, I've established through rolls that she is going to be in the kitchen from X time to Y time, then she is going to bed. If the party shows up during that time period, they will encounter her regardless of their pick locks roll. If the show up outside of that time period, they aren't going to encounter her, even if they fail the roll. She is a preset encounter, not a random one.
Still not quantum, because a preset encounter remains in that location whether they ever go there or not. It's existence is not based on whether the party wanders there.
Nothing about what I am saying is quantum. Nothing is based on whether the party does something or not in order to be in a particular spot or time.