No, entirely different transmission mediums. 'Hearing' requires a pocket of resonant air - and the hot mic is a direct mechanical transmission. This is why you can hear a train coming on railroad tracks for a much longer distance than you can hear it through the air.
This analogy is wrong, astronauts will here things coming in contact with the hard fittings of the suit but the suit itself is not like a railway track. Air would need to vibrate in the suit to activate the mic unless contact was with the helmet itself. There are different mediums involved.
In VOX mode noise levels must be over that of all of the suits systems and even the astronauts breath that is directly in front of the microphone. Look at what the astronauts say. "There is no way for that sound to reach you". When you tap a bolt, or hit with a hammer there is nothing. Even when using high powered drills there is nothing. you simply can't have it both ways.