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.

The hacker slipped past the security system and accessed the confidential data.

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

The technician slipped the cable from the socket and the television went blank.

The employee slipped and accidentally deleted important files from the computer.