2011 MacBook Pros Confirmed To Crash Under Load
sammcj writes "2011 MacBook crashing under heavy load?... you are not alone. While trying to figure out what was wrong with my fancy new MacBook I soon realized that the issue is very widespread."
Having read the linked thread, it looks like it's an ATI graphics card driver problem. You can still ssh into a machine that has "crashed under load".
iStat menu (most probably).
for those tl;dr:
most of the users report that after uninstalling istat menu pro (and it's "fan control" set to on by default) the problem goes away...
keep panicking...