So, just hypothetically, let's say that you were standing just beyond where a railroad track forks--splitting off to the left and right, from your perspective. Currently, it is switched so that an incoming train'll go to the left, but, standing there, you are within yanking distance of a lever that switches the path from one side to the other, if you wanted to.
Now, the thing is, right now there's a train, (driven by a good friend of yours, as a matter of fact, who may or may not be possessed) coming down the main track towards the split at blazing speeds. Furthermore, your family members, and your best friend in the world are standing on the left track--currently in the path of the train's furious rush! if you don't stop the train coming down that way, they will certainly be crushed.
The thing is...On the right side of the track, is your true love. They are from the future, speak several languages, (including binary), are holding a baby that may, or may not be yours, and, if they survive, will invent a cure for cancer. If you switch the track over to the right side...they will most certainly perish.
Beyond this though, there's a group of of Uruk-Hai approaching from behind--they've been sent by Boss Saruman t'snuff you out. Thing is, the left track curves around a little bit behind you...so if you let your family and friend die, it will also kill these creatures in one fell swoop, and save you a good bit of trouble.
Simultaneously, if you change the lever from how it is ow, it will be terrible for the railworker's union.
On the other hand though, if the train driver and your true love both survive, then he will definitely steal her away with his rogueish charm...and then use the cure for cancer to create an evil supercorperation, to the woe of many.
...Anyways. You also have a pistol with a single bullet in, but only enough time to perform a single action--what is it?