I can tell you what it feels like from the front when they fail during shutdown - a lot of crashing and banging, sunroof modification carried out just aft of the cockpit right on the fire extinguisher relays (I think they have now been moved!), and in my case one blade finished embedded in the port fuel tanks. The crewman actually thought the aft pylon was failing, and ran to the front of the aircraft, just in time to see the blade mentioned above coming straight towards him. However, even though there was a fair bit of damage to the roof, all the pipework was still intact, hydraulics still on line (from the APU), and in subsequent inspection the drive shaft was still intact, straight but slightly dented, so the blades didn't desynchronise, which would have been considerably more catastrophic (thank you Mr Boeing).
(Photos will be added when I find them).
Incidentally I was also rung re the incident at Odiham but as mine had occurred 'in the field' there was little I could add to their ideas!