Fact is, you don't get a yellow code by doing a PCR test, you get a yellow code by being near a "red code" person; "near", as in like being in the same place (not necessarily the same time) with a "red code" person. Having a yellow code means you can't go home - almost every place has this device that you have to scan your qrcode and do a facial recognition so that they know (1) it's you, (2) you're on their white list and (3) you have a green code, thus "yellow code" = "no pass for you", and you basically have to wait until the results are out. Sometimes it takes 3 hours, sometimes 5, sometimes 8, sometimes...