Hello! I've already posted a "theory" of sorts on another topic here. I'm doing that again. If you missed the previous topic, here's a link.

Today I'm talking about the oxygen levels in Petravus.

This one doesn't need to be as long, because none of it is based on the genetics of extinct species of Homo. Instead, it's about well recorded science.

So, we already know that Petravus has a level of oxygen that is higher than Earth's by a not insignificant amount. This is evidenced by the explosions from the thermobaric warheads used in one of the more recent chapters (within 30 or so before 170, I forgot the exact chapter). It's stated by one of the characters that the explosion was much larger than they had anticipated.

Now for the main point of this post. Ever heard of oxygen toxicity? Well if you have, then you know that at the very least, oxygen toxicity can cause nausea, among other things, and at its worst, can be deadly.

Assuming that oxygen levels on Petravus are at least 10% higher, we can guess that Choi and Vickers should either be very sick, or very dead.

Of course, there is always a very simple counter argument to a statement such as this. One could simply say, "No, because magic".

With that in mind, take this with a grain of salt, and have a nice timezone.

(On a separate note, I'm not sure what to flair this with, aside from the obligatory spoiler flair. Maybe OC?)