Apparently, the Airsense 10 looks for apneas, and will increase the pressure when it sees them. But it also watches your breathing patterns. It expects each breath to look like a nice bell curve, with the air intake starting out slow, increasing towards the middle, and decreasing at the end. If it doesn't see that, it increases the air pressure in an effort to get you there. While I'm awake, I don't breath in that bell curve. According to the data, while I'm awake, it seems that I take in about the same amount of air at the beginning, in the middle, and at the end of each breath. While I'm asleep, though, I do breath in that bell curve. So, if I'm awake, the machine tends to max out the pressure, trying harder and harder to get me to breath in the bell curve.
The moral of the story is that if I want to try the machine out while I'm awake, I should dramatically lower the upper limit, or put it in CPAP mode rather than Auto mode and set the pressure setting at something I can tolerate.
Also, I'm enabling the ramp feature and setting it to auto, and keeping a tolerable upper limit, so that the machine will give me time to get to sleep before it starts monitoring my breathing and increasing the pressure, and it won't start to inflate me like a balloon regardless.
Thanks again to everyone who responded. And if I've got this wrong, someone please let me know!