If sound is emitted inside a thin-walled titanium container...?

The answer to both questions is yes. You can listen in to a conversation inside a building by bouncing a laser beam off the outside of a window, getting an interference pattern from the vibrating window, converting the changing amplitude of the light into an electric signal, amplifying it and feeding it to a loudspeaker. Your titanium container could be used as an eavesdropping device by bouncing microwaves off it from a distance and doing the same thing with the interference pattern. To shield off sound, you need something soft and dense. Lead sheet is often used as an engine cover on boats for this purpose. A good question.