This is my first time so I don’t know what shrink wrap is!Your probably right about it soaking up the yolk. I won’t do anything to it until I candle tomorrow and see if there’s any movement.
Shrink wrapping is when so much moisture is lost from the egg during incubation that the internal membrane peels away from the shell and contracts down around the chick so tightly it cannot move.
You generally need to have had too low humidity for the entire incubation for this to happen, it cannot happen from leaving the incubator open during lockdown for five minutes.
What could happen is the membrane could dry out and stick to the chick, making it so they're stuck, but that's not really shrink wrapping, and briefly opening the incubator is unlikely to cause that to happen too.
That said, don't be opening it up willy-nilly with no reason. A quick peek in for candling would be fine though.