Bay 12 Games Forum

They are stationed underground in a room after all the traps specifically for that purpose, and they walk all the way through the trap corridor, up the stairs through the main courtyard of the fortress and out the gates before they have line of site with the gobs

I'm relatively new to the game but understand most of the mechanics fairly well (I think). But when I'm under siege by goblins and I station my troops so as to force the goblins through trap ridden corridors to capture/kill as many as possible without my dwarves getting harmed some of my military dwarves simply walk all the way out of the fortress and try to kill the goblins themselves, this usually results in death unless the dwarves in question are some of my higher level military dwarves, how do I keep them closer to their station and stop the unnecessary deaths?
And secondly I've recently built a 19 z-level death pit yet all the goblins and most of the animals that I've thrown into it have survived and sometimes not taken any damage at all, does the pit simply need to be deeper or is there something more to it?
And finally this is my first post on the forums, so apologies for any idiocy or failure to understand basic game mechanics and/or the workings of the forum, thanks for any help!