Even out a run by playing staccato
When a fast run in one hand comes out uneven, Playing staccato puts a staccato dot on every note of the run on the score and plays it to you once, short and detached. You play the run staccato twice, then as written. Only the run's hand is listened to; the other hand can play along or rest.
After a take, choose Practice staccato
It's right under the button that polishes those bars in the result; if that button shows another drill, pick it from Other practice next to it. While you're practising a spot, Other practice in the bar at the bottom opens it too.
Listen once, then play the run staccato twice
The score shows a staccato dot on every note of the run. Let each key go as soon as it has sounded, so the note is over well before the next one starts. After each take you see whether every note was there and most notes were let go in good time; if the notes stayed joined, the result says so and you play that take once more.
Play the run as written
The score goes back to how it's written, and this take carries on your practice of the spot at the same speed. Start playing staccato again whenever you like, or simply keep repeating.
Playing a run staccato is a long-standing way teachers use to even out fast passages. Letting each key go straight away frees the hand and makes the start of every note clear, and always finishing as written carries that into a run that comes out even and light once the notes are joined again.