great effort on keeping the storyline propelling forward, Heavy.
Sorry I happened to mess with yer scene - timing is everything, as they say.
Here's an idea, so as to make it easier to ret-con the scene:
As Ubaar walks forward to intercept the ever-curious and recklessly-impetuous halfling
, he stops to pick up the nasty-looking bone-club.
As he looks it over briefly, Taz continues picking her curious way forward.
He throws the bone back to Kytess, right near Jalon.
"Here's some more runes I can't read.
Lovely."
By the time Ubaar or the others notice, Taz has picked her way up to the end of the corridor.
Ubaar quickly rushes up to meet her, his rushed whisper cutting thru the blackness:
"Taz! get back here, little one!
There's bad stuff here, can't you feel it?"
You could then have the big fugly attack her, and we'll resolve the surprise round.
If so, Ubaar would make sure to interpose himself between the huge imp-looking thing and Taz, backing them both back the corridor towards the others, and placing his faith in the strength of the Thunderbeast, as Jalon's words spring to the front of his mind.
His gore-flecked greatsword takes on a shimmering light of force as he casts Magic Weapon (preferrably before he gets within AoO range of the devil).