I doubt it has affected anything. It just protected itself that's why it shutdown bro. Don't worry, it's safe. Just don't stress test it anymore, you won't be using your laptop to that extent in real life.
Thanks for such a quick response. Really appreciate it. I am new to the site - thought I'd have to wait a couple of days before getting a response!
Could you comment on the 3rd point ?
"It used to shutdown within 10-20 mins of stressing. Last few days, the stressing caused it to shutdown within 30 secs. Surely this must mean that I have angered a component in some way and it will die on me as soon as warranty expires?!"
I think I'll feel much better when a few more people assure me that it's safe.