Slipped

He slipped the pen off the desk and into his pocket.

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

He slipped the key into the lock and turned it quietly.

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

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

The building's safety standards have slipped over the years due to lack of maintenance.

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

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

His physical condition slipped after he stopped exercising.