It can be said that every magnetic disk on the table next to these cabins represents a being that once entered these Sleep Pods.
As for where the physical bodies of these beings went...
[...As you continue your observation, you notice that each sleep pod is connected to a pipe, and numerous pipes extend through the walls surrounding the factory ceiling, intertwining and finally merging into a larger pipe, stretching towards the end of the factory...]
[You follow the direction of the pipes...]
[In the deepest part of the factory, you see a huge spherical device, surrounded by octopus-like protrusions, and beneath the device, is a row of water pipe-like outlets, each connected to a test tube-shaped transparent glass instrument.]
[And a nearby display shows a line of gloomy text: Vaccine Zone — Current Stock: 0 Doses.]
"Zero doses..."
Mu You sighed helplessly.