I just did a Google search on "San Bernadino Mountains + Mountain Lions" and I got a long list of stories about run-ins with them. Given what I'm reading in the news...I don't think you could get me to go on long hikes in the dark through that area.
Here's a nice link to mountain lion behavior, with a few excerpts on how it hunts and how you are likely to die:
http://www.mountainlion.org/CAL_ch4.asp
"Cougars are ambush predators.(44) Like most cats, with the notable exception of the cheetah, they attempt to catch their prey unaware, rather than chase it down. Unlike a bear, which kills its prey through brute force, the cougar is the epitome of speed and precision. The cat is silent on approach, quick on the attack, and efficient in making the kill."
"The cougar fixes its gaze on the animal, lowers itself to the ground in a crouch, and begins to maneuver closer to the animal, taking care to remain hidden. It assumes an alert watching posture: head is stretched forward, the whiskers spread wide, and ears erect and turned toward the front. The cat will hold this position for minutes on end following the prey's slightest movement with its head.(13) When the prey draws within 50 feet or less, Felis concolor strikes.(38)
Flattened against the ground, the cat darts forward, either running or with several bounds, and quickly closes the distance to its prey.(13) The angle of attack is usually from the rear or side.(1) Once at its prey's side it grasps the neck and shoulders with the front paws, claws extended. It will frequently strike its prey with such force during the final charge that in the case of a large animal such as deer or elk, the prey will be knocked off their feet. Although cats will attack from elevated positions such as a tree or boulder, they almost never land directly on their prey."
"The prey is normally killed with a bite to the back of the neck at the base of the skull. The large canines are inserted between the vertebrae like a wedge, forcing the vertebrae apart and breaking the spinal cord.(13) The speed with which this takes place indicates that the concentration of nerves in its canines allows the cat to "feel" its way to the vertebrae in a fraction of a second.(5) In the case of larger prey such as elk, the neck may be broken by pulling the head down and back, breaking it directly or in a fall.(45) If this fails the cougar may grasp the throat, crushing the windpipe. This necessitates death through asphyxiation and takes longer, exposing the cougar to possible injury.(6, 38) The efficiency of the kill will vary, depending on prey size, cougar size, angle of attack, and other circumstances. Hornocker found that cougars were successful 82 percent of the time in attacks on mule deer and elk in the Idaho Primitive Area."
Here's a link to a National Parks page on Mountain Lion Safety:
http://www.nps.gov/pore/planyourvisit/yoursafety_mountainlions.htm
If I had to go, I'd have 4 bright headlamps (facing front, rear, left, and right). I'd carry a Keltec KSG 12 gauge (12 shot capacity) and I'd strap two claymore mines to my backpack to protect against attack from the rear. After that, hey relax...whats the worst that could happen? Oh yeah...I'd also wear a thick leather collar with spikes to keep that cat from crushing my windpipe or severing my spine. I was going to say I'd cover the neck-collar with treble hooks but that might actually make the cat get stuck to you...which would be counterproductive...so I went with spikes.