Just looked at the score. That part is totally playable, there are worse, just look at some of the parts of Rachmaninoff's 2nd Piano Concerto (specially the 3rd movement).
In the past, what I have done with fast passages such as this is set a metronome at very slow speeds (I've started from as slow as 40BPM). At those slow speeds, what you want to do is play each note rather deliberately, yet making sure that you're not using your arm to assist with volume. You want to make sure your fingers move from the knuckle and make sure to keep them in an arch. You may want to raise the fingers slightly higher than usual at this point (remember we're just practicing), which helps you feel the muscles better.
If you have issues with finger strength and find that you use your arm to shove those keys down, then one effective method I was tought at a young age was to practice on a hard surface such as the cover on the piano. You put the cover down, and "play" the passage. The object is, again using the fingers and fingers alone you want to get to the point where you get a relatively loud knocking sound which is consistent among all fingers. Don't rush this, it takes time to develop, specially for the 4th and 5th fingers (the ring finger and pinkie).
Back to the metronome. As I said, I would start from around 40BPM, repeat it 2-4 times, and notch it up by 2BPM. 2BPM is a small enough increment that you don't even feel. Plus you don't realise how many repetitions you're making (repetition helps develop automatic muscle memory, before you know it, you have memorised the notes, you're not even thinking about it, and your fingers go where they need to go, which leaves you concentrate on what's important... the feeling behind those notes, the actual music). BTW, if you're counting that's about 140 repetitions, if you repeat it 4 times per BPM switch moving from 40BPM to 110. However, I like to go past the target tempo, as then when I pull back to the target tempo I feel rather relaxed and comfortable.
That passage requires you to be relaxed and work mostly from the fingers. To help you stay relaxed, you may want to induce a bit of a circular motion in the elbow, following the contour of the figurations, sort of letting your arm "breathe". However, the point is, you're not shoving those keys down with the help of your arm, which is what a lot of people tend to do when their fingers aren't developed enough to help get loudness, which is counterproductive as it's much easier to play fast with the smaller muscles of the fingers rather than the whole arm, as well as it makes you get tense and can lead to issues such as tendonitis.
Hope this helps.
All it would take is about a good 1 month of practicing... Oh no! Not practicing! We don't need that....
