The hypothesized mechanism is very interesting. Perhaps mice vary their behavioral response to pain depending on how safe it is to express distress from pain. VikingCoder has already given the definitive comment: further controlled experiments will tease out how important this effect is over what range of behaviors. There are many, many, many kinds of mouse experiments (I am currently doing reading on behavior genetics research on learning and intelligence and fear and aggression in mouse model organisms), and some will be more influenced by what the interesting preliminary report here suggests than others.

See the book How Genes Influence Behavior[1] for a fascinating description of how we can learn about human behavior by studying mouse behavior (and even by studying fruit fly behavior!).

[1] http://global.oup.com/academic/product/how-genes-influence-b...