Slipped

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 papers slipped out of the folder and scattered across the desk.

He slipped on the soap in the shower and grabbed onto the curtain to prevent falling.

He slipped on the wet tiles and almost crashed into the wall.

The key slipped out of the lock and onto the ground.

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

The quality of the product slipped after the company outsourced production.