The slow-motion effect may be the result of the mind mapping the experience to a single timeline afterwards.

I was at the Enschede fireworks disaster (http://en.wikipedia.org/wiki/Enschede_fireworks_disaster) ten years ago and experienced what the article calls turbo perception. It is not like overclocking a single processor by pressing a turbo switch. A better metaphor may be temporarily having access to more processors than normal that operate in parallel. In a short time frame you make a lot more observations and decisions than normal to improve your situation, apparently some simultaneously. Because it is difficult for the mind to deal with parallel timelines of observations it maps the observations to a single timeline which results in the slow-motion effect that people recall afterwards.