I don't think you can pause the timer in Portal 2. Source: I'm a runner myself.

Even then, if you're not as good and need to eat or do a pp break, just do it. At that point, getting a high time is normal and shouldn't stress you out ;)

No.

When we need to eat something or when we're thirsty we have to go You're not able of doing this while running the game?

You cannot pause the timer in Portal 2, or any games that I'm aware of.

Source Engine games just have great load remover support and they all run on In Game Time, not Real Time, which is why you constantly see the timer stopping.

If you want to speedrun SA competitively and aren't able to play for 4-5 hours in one go, you can do a couple of things:

• Practice your bladder and have food and drinks beside you during the run;
• Pause the game when you really need to go to the toilet, but keep the timer running;
• Run segments (LS%, Badlands%, etc.);
• Run Any% ;
• Run IL's.