Lots of good review comments on the risk assessment video. I like the cartoon-style format, and the narration is terrific.
I agree with what others have said regarding risk being a function of both probability and severity of harm. It's pretty well known that people aren't entirely logical in analyzing risks in their everyday lives (think car travel vs. plane travel), and it would be helpful to address this misconception in the context of lab safety.
The best layman's explanation I've heard on this subject actually came from the pool manager at my local Y. I went there one evening during a mild thunderstorm. Of course, I would NEVER have considered going to an outdoor pool in this weather, but for some reason (doh), it didn't occur to me that an indoor pool would also close. Although the building and indoor pool are grounded and protected, the manager calmly and clearly explained to me that while the probability of someone being hurt inside under these conditions was very low, the potential consequences were so high that the pool was closed out of an abundance of caution. Needless to say, as someone who has focused on safety awareness and safety training for a decade or more, I felt pretty foolish.