I maybe be wrong but I think they just fixed the NPCs running away in the latest patch. One of the patch notes is, "NPCs will no longer run away from anything but the Dark Urge Slayer form to improve interactivity and flow." I'm not sure if that is referring to Dark Urge only or if that means they exclusively run away from that one form and now all other summons are fair game. But I haven't had time to jump back into the game to try it yet.

There is actually a quest where you need to escort an NPC and when we got to the boss the NPC cowers in fear and tries to run away. But because I had an elemental summoned he would run towards the boss and instantly die. At first I just thought that was how it was supposed to be but after defeating the boss 3 times I thought it was way too hard to keep the NPC alive and it didn't really make any sense for him to run straight in after dialogue saying he doesn't want to go in there. The quest/dialogue also acted like he was still alive so it's as if the developers never even planned for the possibility of him dying in that area. On my 4th attempt I moved the elemental in front of the door and sure enough he ran the opposite direction and stood in the corner he was supposed to, safe from the fight.