Tesla Roadster safety

I speculated earlier about the safety of the battery system that Tesla Motors is using.  Here's a great article from Technology Review with a lot of specifics.  One claim was that there have been about 1 in 10 million laptops that had the exploding problem that I alluded to earlier.  However, the Tesla has 7000 batteries, so maybe only 1 in 1000 Roadsters would experience the problem.  The engineers at Tesla have put them in steel cases, triple fused them, and have some sort of apparently active liquid cooling system.   

This sounds very good.  I'm feeling positive about getting a Roadster.  But what if you're in an accident where there's a bunch of burning gasoline from the other vehicle?  Could that lead to a chain reaction with the batteries?  Even if it could, the same thing could happen if you were in a gasoline car, so it's not really a deal killer unless the resulting explosions are really large.