As the title says, they suck. Hate seeing this recent change at slashdot, the only change on any website that I frequent where I've actually taken the time to email the admin for feedback about anything. Love this site, but hate the videos. Give us a filter, where those of us who hate seeing that crap on the front page can weed it out by default.
Without a doubt, heart attacks. I work with lab mice every day, and they're very high strung creatures. When we order mice from a supply house they often pack in one or two 'extra' mice in the event a death occurs in transit. This is just regular shipping via truck/plane, so the stresses of going through a launch into orbit being so much more I'd expect a high mortality rate.