How do you get 2m in 30 minuits on RuneScape

that is impossible unless you hack Jagex, which is illegal and can permanently delete your account.
You could go to the Falador Party room and wait for someone to drop that much money, but it probably wont happen, and you have about a 1.32529362% chance of even getting 1gp because if someone drops that sum of money there'll be a lot of people and you probably won't be lucky even to pop a balloon. Just aim for 100k in one day, cause it is a lot easier, and it's still a lot of money.
If you are a member, have completed the Rune Mysteries Quest, AND you have level 50+ mining, you can mine Pure Essence. In 45 minutes, you can have 150k =P. In 5 hours, you can have 1M gp. So, if you want 1M a day, mine pure ess constantly and eventually you will get 1,000,000 GP.
You could sell 2m worth of items all at once, but does that really count?
Not really cause you have to buy that stuff in the first place =\. unless it is trees then it would count

this takes more than 30 mins it could take a long time maybe but here we go you could chop down a lot of willow trees (need to bee lvl 30 woodcutting)and put them in your bank do this multiple times till u have about 2800 then go to the ge and sell them