Hmmm,
In Med School, I rode a VMAX while living in a "studio" apartment. Of course, I would NOT park that thing in the lot, so I put in on the porch every day. Well, they busted me. So I drove it INTO my studio every day, using the motor to bump it up over the doorway hump, then shutting it off.
The point is that the size of the apartment was about as big as your average one car garage, and I never got sick. I studied in there for hours at a time, no problem. Occasionally, the fumes would be strong, particularly after parking it, but I got used to it. No problems.
Of course, it's probably not wise to do so, but if you're in a pinch, it probably won't do much harm. No more than the amount of damage you get from an average drunk.;)