UNIT in brisban broken
One thing you can do is submit a bug report under Support/Bugs, Game, Forum, Website. When in-game put /IP in chat to check which IP it is and add that to the report. I found it got fixed pretty quickly once they know what IP it is happening on.
Here is a link to one of my reports:
https://forum-en.gw2archive.eu/forum/support/bugs/Bug-Unit-Event-in-Brisban/first#post4750931
The event seems to bug when folk go too far ahead and kill stuff especially the golem in the niche just before you get into the room in the inquest facility. The wiki does have some bug info that also might help.
https://wiki.guildwars2.com/wiki/Help_U.N.I.T._find_and_destroy_the_Inquest
" Bugs: If U.N.I.T skips the Inquest Assistant and the Mark II Golem and enters through the north door into the final room, and instead engages inquest inside the final room and enters though the east door, it proceeds to clear the room and free Wistt from his cell, but stays in combat mode as if the room is still not cleared, causing the event to not proceed to the final dialogue and progress to its final phase. If this happens you can unstick it yourself but getting UNIT killed. To do this, just kite in enemies near UNIT and he will attack them. You will need to get several. If you can get the Prototype Robot and 1 other, that will work."
I hope this helps you get the event restarted so you can work on your Giant Slayer.
I know that i only have to lure Prototype into fight e.t.c.
But there are to many helpful players who always help UNIT in not getting killed so the event doesn´t finish.
And I summit a bug report every time. I just want to kill giants.
Give us giants.