What oil were you using ?
It's kind of odd that would happen without any prior noise. I'm also sure you were not expecting it so you were not intent on listening to the engine sounds.
Yes, do let us know...
201,000miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. CHECK your oil, these cars use it.
Engine Build - Click Here