Sergei trained me today. He wants us to go into the Green soon. Xi won't come, but he's making progress persuading her to go into the Yellow. My guess is that she won't be relieved if I'm not a competent senior researcher. To prepare, I learned more about the Zone system.
Sergei told me that the standard model of The Sick Land - with a Green outer ring, a Yellow inner ring, and a speculated Red centre - is an approximation. The topology of The Sick Land is more like a heat map, with localised hot and cold regions within a general band. These regions are dynamic; the effect on a broad scale is the three Zone system (or two? We don't know if there's a true Red Zone, as nothing has ever made it past the mid-Yellow).
The strength of the mal on an area varies, not only with distance from the supposed centre, but with many other factors, lots of which are opaque to science right now. Fluctuations, and the expansion of The Sick Land, are products of this variation in the mal. Sergei told me that the way to do good research is to find 'bubbles' of Yellow in the Green. That way, you can get good specimens and take important measurements without exposing yourself to unnecessary risks.
I asked him how deep he'd gone. He stared off into the distance for a while, then grunted. Apparently the outer Yellow was deep enough.