How do ethical guidelines make science safer?

Well, for one thing, they ensure that a scientist can't claim a certain result, which might be biased and thus inaccurate, because he or she is being paid by, say, big business interests. For another, they ensure that medicines or treatments can't be made available to the public without thorough testing, replication, and peer review.

ethical guidelines are made to be implemented together to make any type of ethical judgment.

ethical guidelines make science safer because

It provides restrictions to the scientist, they can't claim their results, which may be inaccurate or would cause any harm to the surroundings and society. As per the Ethical guidelines, researchers are allowed to follow certain rules while conducting out research, so that their work does not cause any harm to the environment and participants.