Hi Lelle, thanks!
I suppose a large part of the problem is tension. I get all nervous when I hit the speedwall in this piece because I want to get it right so bad🙄 Do you have any tips, exercises for relieving tension? Thank you! 
Is it the place with the thirds? If I try to write advice it'll unfortunately be terribly generic but I'll try. Try it out, see if it helps, if it doesn't, ignore it.
The first awfully generic thing I'll say is that the best way to get to this goal is to hurry slowly. The more you try to force it the more problems with tension you're likely to have. So practise slowly and patiently and don't try to force the tempo, and you'll paradoxically make faster progress.
First of all, check that your hand and arm are relaxed when you are not playing; wrists, elbows, shoulders are all relaxed and fingers are soft like cooked spaghetti and that you feel comfortable and relaxed when you sit at the piano.
Next, can you bring your hand to the keys, and then press down one key to the bottom, keeping the non playing fingers and your wrists just as relaxed as before? Try this and check if you are stiffening up anywhere in your arm, wrist or hand. Figuring out how to be able to press down keys to the bottom without stiffening anywhere in your hand or arm is an important step in the right direction. Once you can do that, you can start stringing together multiple keys played with relaxation. Work slowly and check that you feel calm and comfortable.
Also if you get nervous and are anxious to hit your goal it might affect your breathing which in turn will tense you up. Are you breathing calmly and easily, like when you chill in the sofa and watch a relaxing video, or does your breathing get shallow and tense? if you can train yourself to continue breathing calmly and easily when you play, it'll also help a lot.