I have decided to try and circumnavigate the lake (to look for good places to site a tribe). Anyway I got to Zone 228 was quite happily trotting along and all of a sudden I fell unconcious, i wasnt in a green cloud area, so it looks like a couple of section of this zone are toxic. It took me about 5 or so minutes to run out of that area keeping as close as I could to the edge of the lake. Then I was ok and then about 5 mins later fell again and then the server went down. So be careful around zone 228!!
It could be the Area 51 of Xsyon!