That, strictly speaking, (from the photograph at least) isn't a Eurostar, but I get the point.
Uhh. The channel tunnel has a pretty impressive safety record. 15 years of service and no (Or so I think) deaths (There have been reports of fatalities of asylum seekers getting hit in the service tunnel, but those are pretty much conspiracy theories about UK government cover-ups.)
In theory, the eurotunnel employees were just talking crap. The ventilation systems in the tunnel (Consisting of two huge systems at each end) were running fine, and air was certainly circulating the tunnels, but the fact is the air conditioning and insulation on the trains was just too good. Opening the air-conditioning cocks (make a joke plx) would have given some natural ventilation, but that can only be done from the trackside, and none of the regular employees were trained.
Eurostars run at 186mph, weigh almost 800 tonnes, and have seats for 750 people. There are 31 to maintain and run, and the technology used isn't much different from TGVs of the 1970s. Maintaining a 400 metre train is no mean feat, and one electrical short can put the whole thing down.
It's not that massive a fault, but it's weird that they didn't send any rescue services in sooner.
ITT: The brits+frenchs that were trapped will probably live. And it's not like it was some huge case of negligence, it's a design fault made by a frenchman/englishman some 15-30 years ago (depending on when the underfloor equipment was designed)
Edited:
No, the thing is that in a 20 mile long tunnel, there won't be a lot of fresh air coming in. If you use up the oxygen in the middle, you'll suffocate unless you've got some means of circulation, or a real strong wind blowing in.
Try breathing through a 20 foot snorkel. The effect is similar. (actually, don't try it underwater. You might die. Seriously.)
There are huge ass fans at each end of the tunnel for ventilation, and they were all running when it happened. "Breath less" wasn't really neccecary.