In two films about the Titanic, Murdoch was portrayed shooting passengers and himself during the sinking; this was based on a number of eyewitness testimonies of a shooting/suicide by an officer during the launching of the last lifeboat. It is possible that Murdoch was the officer.
In general, to append is to join or add on to the end of something. For example, an appendix is a section appended (added to the end) of a document. In computer programming, append is the name of a procedure for concatenating (linked) lists or arrays in some high-level programming languages.
An appendix is additional information or material at the end of a document. Appendices allow writers to provide images, product descriptions, or data that supplements the main text but would be distracting in the body of the document.