The cobas 8000 is huge: https://www.youtube.com/watch?v=Aht-L4BMyN4
https://www.youtube.com/watch?v=6P-jaC3_d3o
The dramatic trailer music is quite adequate, IMHO.
[0] https://www.gsaadvantage.gov/ref_text/V797P7347A/0UZLK9.3QPY... , page 13
But good point about cross contamination, still could be there is a mechanism to counter that, like some vapour pressure tricks or gas streams preventing fumes from one open container reaching another.
The tests are detecting levels of antigens, antibodies, or DNA in the sample. The samples are manipulated with disposable parts to prevent crossover.
Technology is great. Before this product it would probably take an entire university campus with multiple labs full of technicians to do the number of tests this is doing.