いきなり (translations)→ abruptly beginning bluntly directly fast freely instant instantly leap new out-of-the-blue outright point-blank pointblank promptly sudden suddenly unannounced violently
だしぬけに (translations)→ immediately surprisingly unexpectedly
とっさに (translations)→ quick quickly still
思わず (translations)→ automatically briefly inadvertently instinctively involuntarily unconsciously unintentionally unwillingly visibly
反射的に (translations)→ gut reflectively