Even out a run by playing it as chords
When a fast broken chord in one hand, such as an Alberti bass or an arpeggio, comes out uneven, Practice as chords gathers each beat's notes into one chord on the score and plays it to you once. You play the chords twice, then the run as written. Only the run's hand is listened to; the other hand can play along or rest.
After a take, choose Practice as chords
Where the run is a broken chord, it's at the top of Other practice, which opens beside the practice button right under the one that polishes those bars in the result; when the practice button shows it, it starts from there. While you're practising a spot, Other practice in the bar at the bottom opens it too.
Listen once, then play the chords twice
The score shows each beat's notes as one chord, a beat long. Bring all of each chord's keys down at once. After each take you see whether the keys of every chord came down together; if a chord spread a little or came out rolled, one key after another, the result says in which bar, the score circles that chord, and you play that take once more.
Play the run as written
The score goes back to how it's written, the chords open into the figure again, and you see whether the run came out more even than at first. This take carries on your practice of the spot at the same speed. Start playing as chords again whenever you like, or simply keep repeating.
Playing the figure as chords puts the whole hand over all its keys at once, so it learns the shape and the distance between the fingers before it has to play them one after another. Open the chord back into the figure and the fingers are already over their keys, so the notes fall more evenly. Bringing a chord's keys down exactly together shows the hand really holds the shape, and you always end on the written figure, because that is what you're polishing.