If you're being chased by a crazed knife wielding maniac, a chainsaw wield, or Martha Stewart, then you definitely have to fall down. When do you fall down you may ask? All the time, if you're running through a field, trip and fall. If you're climbing up the stairs, trip and fall down them. This is the only way to survive the massacre that killed your friends, all because they didn't fall down enough.
See that police station over there next to the old haunted slaughter house? Which should you go in? If you said police station then you are wrong my friend, and also probably dead. The police station would be the first place the serial killer would go to find you, while the slaughter house is the least likely place he would think to go for victims.
You just jabbed a coat hanger in his eye and then shot him six times and now he's just lying still on the ground? And you think he's probably dead. Great, but if you think there's a chance he may still be alive then make sure to stand next to his body so he is too scared to get back up. Also, when he does start to get back up, don't move, stand your ground to show him that you mean business.
When in danger of a being brutally murdered by a psychopath, always split off from the group and wander around on your own. This will confuse the killer and make you the least likely to be killed. And besides, I'm sure one person against a maniac will fare better than a whole group anyway.