jerk, jolt
raid
deed
crackdown - for the That's Life! puzzlers
Crash is a 5-letter word that can refer to "a sudden noise".
The word punitive if defined simply basically means "punish". So to take sudden punitive action would be to take sudden disiplinary action essentially.
onrush
craving
Sudden
Unexpected
fervent
A four letter word starting with the letter a is able.
Impromptu is the closest to spontaneous word. It is a word representing sudden action.