Block the Gate and Let Them Fight Their Way In
When I'm running Dungeons and Dragons one of the things that I like to set up is a choke point. I like letting my players find them and watching them devise ways to stop their enemies from making the big push that will assure them of victory. I like that these locations almost force my players to be the heroes of the story as they make the hard choices that most of us (hopefully) never will.
In real life so few of us get to be the real heroes of our stories. Instead we swallow our pride and muddle our way through the insults that people fling at us - it's so much easier than making waves. But role-playing games are our opportunity to be the hero; and being allowed to make the grand sacrifice to ensure that your fellow players, or the kingdom you've spent so much time investing in, survive is one those special things that only comes up if you're lucky. So why is it that I'm seeing so many examples of people refusing to take that moment and make it theirs?
I'm not saying that you should make a foolish sacrifice and needlessly waste your life; you're one of the main characters in the game and that makes you too important for such foolishness. Yet when those moments come up, where sacrificing your life will save everyone important to you and your story, why waste it by running away like a coward? Why let your lasting memory of that campaign be the missed opportunities to be great and heroic?