Using Chrome 24.0.1312.57 on OSX.
Tried Lab: HOL-OPS-04.
Took around 30 minutes to start, but did get there.
Got to page 34 and then the Control Center VM locked up, unable to click anywhere. Left it for 10 minutes, but in the end reset it (screenshot 23.07)
After reset, it logged back in, but then locked up straight away (screenshot 23.25)
Seeing smoke drift across the Atlantic, I gave up :-(