Slipped

The book slipped from his lap and onto the floor.

The spy slipped the secret code into the message, without anyone realizing it.

The secret plan was slipped into a confidential memo, without anyone noticing.

He slipped the ring from his finger and into the box.

The bag slipped off her shoulder and spilled its contents onto the sidewalk.

The piece of paper slipped from the bulletin board and fluttered to the ground.

The spy slipped past the guard and entered the building undetected.