How long can a Playstation-2 go without overheating?

I’ve had my Playstation 2 running for about 8 hours now… The problem is that I can’t turn it off because I have no memory card, and I’ve been playing my new game for eight hours. So if I turn it off, I’ll lose all my data (I expect to be getting a new memory card in 3 days or so)
Is this safe? Will my Playstation 2 last that long? What’s the general amount of time these consoles go without overheating or stop working from being left on?