How can I lose either a) 30lbs in three weeks or b) 2 inches of my waist in three weeks?

You can't drop 30 lbs of fat in 3 weeks. That's more than 1 lb of fat a day, and plenty of people work hard to drop 1 pound in a week. Consider that you need to 'burn' 3500 more calories than you consume, to lose 1 lb of fat. If your body burns 2000 calories in a typical day, and you ate zero calories, that would give you a calorie deficit of 2000. So, you'd need to create another 1500 calorie deficit just to drop ONE pound in a day/ So, you exercise like crazy and are able to burn another 1500 calories. In one day you were able to 'burn' 3500 more calories than you consumed (because you consumed none).

That's just 1 day. Since you aren't consuming any calories, your body has no nutrients for energy. You wouldn't be able to keep up your crazy workout pattern on zero calories, and as the days go by, eventually your body won't burn 2000 calories a day as it's standard amount because it will know it needs to conserve energy since it's not consuming any calories. So your metabolism slows a bit so that your body needs fewer calories to perform all the functions it performs to keep you alive. It wouldn't be many days before you wouldn't have the energy for a decent workout, so the ability to get the needed calorie deficit to drop a pound of fat (or more) each day would quickly vanish.

As for 2" in your waist, that's the easier goal to reach, although I don't know if you can do it in 3 weeks. Some things to do are IMMEDIATELY switch up your eating to cut out as much processed food as possible, and no added salt on your food. Fresh meats, fresh fruits and veggies, should be the main part of your diet. Processed foods are often high in salt as well as other preservatives and chemicals that aren't good for you. Use spices and herbs to season your food (not salt...at least not for now)

Drink lots of water. TRY to drink half your weight in ounces of water, daily (so if you weigh 150 lbs, your goal would be to try to drink 75 ounces of water a day...spread throughout the day). Don't try to drink a whole lot at one time, because what your body doesn't need will just pass through. Take a swallow of it every few minutes all day long. If you're eating a lot of soup or fruit or other foods high in water content, that can count toward part of your goal of "X" ounces.

Look up waist exercises online or youtube videos that work your waisltline. By working the muscles of your midsection you'll help tone and tighten them, so they become more compact and help hold in your tummy. Expecially work the oblique muscles, which wrap around the sides of the waist.

With a combination of 'clean' eating, lots of water to help flush retained fluid out of your body, and really working hard on toning those muscles around your waist, you might be able to see an inch or 2 difference in your waist in 3 wks, even if other parts of your body don't show a significant change in size.

Adding other cardio exercise to your daily routine, but burn extra calories would be a plus as well.

Not on any way that is healthy for you. Losing that much weight so fast is dangerous. Don't listen to idiots who tell you that you can.