あっという間に (translations)→ immediately quickly rapidly swiftly
いきなり (translations)→ abruptly beginning bluntly directly fast freely impulsively instant leap new out-of-the-blue outright point-blank pointblank promptly sudden suddenly unannounced violently
きっぱり (translations)→ absolutely assertion boldly determined firmly sharply sternly stoutly tersely
さっと (translations)→ brief briefly briskly casually effectually fling lightly quick severely sharp swing whisk
すかさず (translations)→ already automatically simultaneously smoothly straight
すぐ (translations)→ close closely dutifully easily easy first instantaneously just minute now present presently pronto quite right simply soon then very willingly
すぐさま (translations)→ immediate
そのまま (translations)→ consequently continue docile exact frankly keep let originally perfectly plain remain same there unconsciously whole
たちまち (translations)→ completely hastily instantaneous momentarily short speedily
たちまちのうちに (translations)→ sight
ふと (translations)→ accidental chance dare inadvertently involuntarily momentary unbidden unexpectedly when
みるみる (translations)→ dramatically perceptibly visibly well
急に (translations)→ begin considerably hurriedly snap
瞬間 (translations)→ as flash moment situation time
即座に (translations)→ automatic impromptu readily
すぐに (translations)→ forthwith in a bit inevitably straightaway
