IIRC 10.99 and quicker is when you need a blanket and a flex shield to race legally. Never actually witnessed a 727 blow through the floor pan but I've seen plenty of pics and it's not something I'd want to experience
That having been said we ran the car deep into the 11's for a season or 2 before fitting all the safety stuff and billet front drums etc. If you are sensible and burnout correct you will diminish your chances but you'll have no control over track conditions. In hindsight I feel I may have been a little foolish but didn't really know any better at the time