I don’t have a screenshot of the incident because we all died so fast, I’ll have to describe where we were. This incident happened on Halescourge late in the map, past the second Grim there is an area that slopes upward towards a big gate. At the bottom of the slope there is an archway. My party was in a loose line fighting a horde in that archway when twitch mode decided to spawn some packmasters. However it spawned them literally on top of two of my teammates, which resulted in them being grabbed and instantly dying to the horde right in front of them. There was no way for them to react in any way.
Twitch spawns work differently from regular specials in that it spawns them as a group and closer to the players than normal. But in this instance there wasn’t enough of a minimum safe distance around the players.