Trick-or-Tort
Halloween is just around the corner. People are always asking, “Siouxsie, what if I scare someone to death on Halloween, could I be sued, would I be liable?” Apparently, yes and no. The world is full dimwits and desperate attorneys (see, e.g., this one British firm) who are chomping at the bit to sue witches, goblins and other creatures of the night. But in most cases, juries are not sympathetic to these spoil sports.
For example, last year a witch scared her clumsy Gladys Kravitz-type neighbor in Baltimore on Halloween. In this case, the neighbor fell and broke her elbow and promptly filed a lawsuit for $500,000. Not to worry. This case has a happy ending. Apparently, the jurors sympathized with the witch and imagined themselves similarly spooking a neighbor. Judgment was entered in favor of the witch.
Please note, there are no cases of record that deal with injuries sustained from actual demons summoned to wreak havoc on trick-or treaters on Halloween. Juries may not be as sympathetic to such a fact pattern.
Siouxsie Law 
“For example, last year a witch scared her clumsy Gladys Kravitz-type neighbor in Baltimore on Halloween. In this case, the neighbor fell and broke her foot and promptly filed a lawsuit for $25,000.”
Wow, I totally didn’t get that set of facts from my reading. She didn’t actually scare the neighbor, but she was acting as a witch to ‘scare’ the kids, and her neighbors went onto her property to join in. It was then the neighbor tripped. BIG difference here from the original fact pattern you set up, where you make it sound like the defendant scared the plaintiff who was then hurt when trying to escape/leave/run-away.