I always figured it would suck the most if your house was on fire.

Luckily SP rarely lasts longer than a few seconds/minutes, with about 8 minutes being the upper range in people with serious sleep disorders. A few cases like this are extreme examples of the danger. In this case, it seems most likely that you were in REM sleep (and rem atonia) and weren't able to breathe, which woke you prematurely, hence giving you the SP. My point being, you being in SP was probably a direct result of the trouble breathing in the first place. Of course this is all Shifty speculation. But still.