good question

Think of it this way:

- Each civilian has trigger area associated (aka each civilian will need an area created in editor)
- If player X enters trigger area, Civilian runs to specific waypoint on map (or can choose a random waypoint from available set)

It is also possible to script it via engine interactions (aka what's being done with frag grenade and soliers running away from it). However, that would be a little more involving.

there's a "civilian" behavior. somewhere you cab change the behavior from "soldier" to "civilian" in the editor