Without any warning (3,2,1,6)
I believe the answer is:
all of a sudden
(Other definitions for all of a sudden that I've seen before include "Without warning" , "In an unexpected manner" , "Quickly and unexpectedly" , "abruptly" .)
I believe the answer is:
all of a sudden
(Other definitions for all of a sudden that I've seen before include "Without warning" , "In an unexpected manner" , "Quickly and unexpectedly" , "abruptly" .)