Set Piece
Set Pieces are a weekly look at an encounter you can use at your table. These small scenes are modular in nature and can be slot into adventures rather easily. I will discuss the tone you can take in these scenes, the enemy types you can encounter and different options that you can make that will affect how the encounter could play out for your players.
(the following Set Piece is an expanded take on and encounter I wrote for D20Radio’s GM Holocron. If you are a fan of Star Wars and Star Wars role-playing you should take a look at d20radio.com and their Order66 Podcast)

Bad Shaft
Terry’s grip on the rope was slipping, Kate said the harness should hold him, but he had his doubts.
“Hurry up would you,” Kate called from below. “Or I’ll unhook this rope tied to me and leave you up here alone”
Terry slowly continued his decent, but then a crash came from above. Terry looked up but his headlamp barely illuminated 10 feet.
“What the hell was that?” He called.
“I don’t know, but I don’t like… Hurry up Terry!”
“Look out!” Terry called as the rusted metal shield they had wedged in front of the shaft’s entrance came crashing down from above. Kate propelled herself off one of the walls and her and Terry barely avoided the falling shield. Terry looked down to see if Kate was alright. Kate’s eyes were filled with terror as she was looking up… up past Terry to the shaft’s not so hidden entrance.
“Ohh God… it’s coming!”
Scene:
The elevator is busted, the mine shaft has a lift no longer, or there is something shiny deep down in the well; for whatever reason, the PC’s are climbing up or down a very confined corridor. What a great location for an intense encounter.
The encounter works best if the threats are coming from the opposite direction that the players want to go, and not something they have to fight through in this space. The scene is best not as a straight fight but rather a desperate escape or a chase.
Mood/Threats:
The type of threat really sets the mood in this scene. A mindless horde or horrific monsters make this a desperate climb or decent, with a possible struggle here or there as a fast creature makes it to the players.
If the threats have ranged weapons things turn a bit hectic but less desperate. A firefight as the players position themselves under(or above) bits of machinery or side support beams make things play out differently. However, if their threat is above them, they may have to watch out for things they hit falling down on top of them.
Another take is having the threat environmental, rising lava, water, or an encroaching gas would make the climb just as desperate but change the threat from an enemy to something more inevitable.
Mechanics:
Athletics or Climbing checks should or course be used in this encounter, but not every round. If the players have a rope or climbing gear, or other means to making climbing easier they shouldn’t need to roll just to climb up or down at a normal pace. However, if they are trying to go fast, or make a difficult maneuver, or a ghoul has jumped on their back and is about to bite into their neck, then you should probably have them make a check to make sure they don’t fall.
That said a failure on a check doesn’t mean they fell. They just weren’t able to find purchase on that other wall or got held up and moved slower than expected, only a critical failure, despair or GM intrusion should have them falling into the depths. Even then some other save, or another player should be given a chance to save their friend.
Fighting of any kind should be made more difficult due the climbing situation.
Tips:
Keep the players moving. Forward moment is key to this scene being memorable rather than a slog. If the players want to stay and fight the threats, ramp up the physical checks by having their ropes get cut, or climbing pick start to break. If the players are getting bogged down with the threats, introduce and environmental one that affects both friend and foe to thin the enemy ranks and break the players free. (a sudden explosion from above rocks the ground, water cascades from above…)
Don’t drag out the encounter unnecessarily. If the players make great climbing checks to get out of their super quick let them. Play up how big the horde is and how horrible the scene is they are leaving behind. Make it feel like their skill saved them from a horrible fate. Make them hope they can find ANOTHER way out.