IMHO Aikido principles and techniques including real full power atemi work in any environment. Imagine what you could do in an elevator using your Aikido training in a life or death struggle. Imagine what Steven Seagal would do in that situation to stay alive and you get the idea.
By the way, my Aikido training and my training in Military Police tell me to always evaluate the situation before I get into the elevator and when to get out of the elevator when others get on it. ZANSHIN at its finest!