Why not "do it quickly"?
I think that should be the right answer. Did you report it?
I answered "do it fast" - was wrong - shouldn't it be accepted?
Haraka (invariable) comes from Arabic حَرَكَة (ḥaraka, "movement; commotion; physical exercise; stirring, impulse; vowel").
Why not 'hurry up'?
"Hurry up" would be the usual expression in English. "Do quickly" isn't normal English.