Red, Wikipedia is not the Bible, or even the ultimate font of knowledge. I really get tired of people referring to it as the ultimate answer to all questions. It is merely a site offering some facts embellished with opinions of the contributors including their interpretation of other opinions.
The Catholic church is not flexible regarding the circumstances that lead to the person's death. If it was suicide, then it is a mortal sin. I believe though that the bodyguard scenario would not be considered suicide since he isn't the one actually firing the gun nor is he jumping in front with the purpose of ending his life but trying to protect another at his own expense