NPC with broken script freezes the game on hello

When an NPC has a local script that cannot be compiled ties to say hello the game freezes. Or rather, it becomes impossible to move, the menu still works.

This is caused by the dialogue system attempting to check the NPC's local variables to find a matching voice line. To do so it compiles the script, which of course fails, but that doesn't prevent it from trying again. And again. And again.

Affects the slave trader in Suran added by Traveling Merchants.