If you're assuming the time shown is how long it ran until it had to be shutdown, no - That's not it.
That's simply how long it took to complete the computation of that particular bench.
With higher frequencies you do get more heat generated since it takes more voltage to get there but that doesn't mean the system has to be shutdown immediately. You will see a spike in CPU temps once the bench begins to run = When the CPU begins doing work and that's natural, something you'll see even at stock settings.
The thing here is how high do temps get while the system is under load.
Your cooling used, voltage used along with other factors all figures into the final result of where your temps wind up being. Also know great temps at idle are meaningless, temps under load tells the story.
Here's the other run with that chip on air so you can see I didn't have to shut it down right away:
http://hwbot.org/submission/850844_bones_wprime___1024m_athlon_xp_m_2800__2298sec_750ms
As long as temps don't get too high while the bench is running it can keep going and that's the whole thing about it - Keeping temps under control while the system is under load/doing work.