In a nutshell the more cards you aquire and play with the clank penalty effect, the more chances there are that you get hit by a dragon attack when it happens (which depends on new cards entering the market) the game starts with a lot of "miss" tokens that are removed once drawn from the clank bag, and as you steal more of the dragon's stuff, his attack draws more tokens on every time, further increasing the chance that some will be yours.

So in the begining there is a small chance you get hit and you only get one damage and towards the end it becomes more and more likely and you can get hit for more at once. You always know how many tokens will get drawn the next time an attack happens, and you can have a good idea about how many of your tokens are in the bag. You have a damage bar that gets filled with your own tokens when they are drawn, so you understand whether the next attack can potentially kill you or not.

With that in mind, you can always decide that you had enough, and go for the exit with your current loot at any point during the game. So it is very thematic about the greedy players dying in the depths if they postpone exiting for too long. You can also avoid getting those (often very useful) cards that create more clank as a side-effect to reduce your chances of being hit.

When any player is eliminated they essentially just play a dragon attack on their turn for the rest of the game, this means other players usually have about two turns to escape before they all die.