Interesting phenomena

So I just got back from an amazing end-of-year party at my classmate Sophie's hose house - thanks so much Sophie, we love you in a non-creepy friend way - and my phone apparently died sometime during in it - it was in my pocket so I don't know exactly when, but the battery was pretty low. By the way, I got a Galaxy Nexus, which is running Android 4 (Ice Cream Sandwich).
Anyway, I was experiencing an interesting phenomenon like 40 minutes ago (it was 5 when I started to write this, haha), which was this:
Basically, I had my phone plugged in to USB (on the side of my MacBook Pro - this is important as side USB ports tend to not be as high-powered as rear ports). And I would turn on, and it would boot normally, getting to the lock screen each time. But here's the thing - it would turn off randomly. Once, it turned off as soon as I got a notification (it happened to be from Gmail). Another, because on boot, Android doesn't prompt you with Face Unlock and instead falls back on your PIN/pattern/password by default, only I wanted to use Face Unlock for some reason, so I put it to sleep and then turned it on again (which is how you get back to Face Unlock from the fallback method screen), and as soon as I saw an image from the camera, it died. After this particular episode, I said "hmm, what about the camera would cause it to die?". The only thing I could think of was that either something about the software driving the camera was crashing the system - doubtful as this system is relatively new (it'll be 3 weeks tomorrow) and I haven't tweaked anything low-level or rooted it or anything - or the camera was using too much power.
So basically what was happening was that the phone's power level was on a very fine threshold - USB power was keeping it alive, but just barely, barely alive. The increase rate of power must have been incredibly tiny, as the system barely had enough power from USB, and the battery was completely drained. And when even a tiny thing like a new notification caused a (equally tiny) spike in power consumption, the phone would be pushed into a negative rate of charging (so it was using more power than it was getting), the phone would recognize that it was a. in a critically low power state and b. discharging, and it would die. I found it especially interesting that when the phone died and was in a completely off state, it could charge unimpaired (albeit for not that much time), as the system wasn't using power resources; therefore, it took progressively more to push it over the limit - for comparison, a new notification vs the camera turning on.
Now I want to talk about lucid dreaming as my second interesting phenomenon, but I'll do it in a separate post. I basically just mention it here so I can keep the word phenomena in the title (otherwise I would have to change it to phenomenon), because I like that word.