treacherously (adverb)

1. In the treacherously dark alley, the detective silently followed the suspect, creating a suspenseful scene in the movie.

2. The protagonist's best friend treacherously betrayed him, adding an unexpected twist to the plot of the novel.

3. Judas Iscariot treacherously betrayed Jesus with a kiss, leading to his crucifixion in Christian theology.

4. The treacherously haunted house revealed its horrifying secrets as the protagonist ventured deeper into its dark corridors.