I'll say that you trust Xavier's words and follow through with your initial action, minus the move (he did say to stay put). Instead, you just reposition yourself at point, along with Reli and Mr. Benson, with Leena just behind.
--
Xavier takes his turn to fly above the wall of thorns and manifest his wall. The dragon look sat you all suspiciously, but comes forward in flight, colliding with the wall.
Ah! Cowards! You mean to delay your destruction?!
The Wall of Force is placed halfway between you all (20 feet or so), meaning that the dragon uses 20 feet of movement in coming into contact. The wall is placed in a square, 50x50 feet. Not knowing the dimensions, she snarls.
Trickery! No matter!
She then climbs 50 feet up (her fly speed is 80), feeling the invisible wall, until she is almost over it. She remains on the opposite side, hovering and using the wall as cover. At this point everyone can assume that there is an invisible wall there, and it looks to be about 50 feet high. You are not sure of its width.
This puts her a good 55 feet away, diagonally (20 feet back, 50 feet up) from Arcivus and the front row, about 60 away from Leena, and about 70 away from Dr. Nimm. Xavier took his action to fly up, so he is actually closer at around 40 feet away.
Yes (a^2)+(b^2)=c^2. I am solving for the hypotenuse in each case.
The dragon seems to be ready to defend herself midflight, at a moments notice (Dodge action).
This ends the first round. Everyone seems pumped and buffed up.
--
Round 2!
Leena, seeing that an arrow would be a waste of time, quickly repositions herself.
We should spread out now, to not get caught in a breath weapon! (In Elvish) Reli, with me!
She then proceeds around the right side of where the dragon is hovering, but doesn't seem to make it to where the wall might be. She and Reli then stand at the defensive.
She curses the dragon in draconic, in an attempt to goad the creature.
@!*&%*$#@!
--
Initiative:
Leena (29): Hunter's Mark (c), Aura of Purity
Dr. Nimm (21): Aura of Purity (c), behind thorn-wall
Xavier (21): Aura of Purity, behind thorn-wall, flying, Wall of Force (c)
Arcivus (18): Aura of Purity, Death Ward, Freedom of Movement, flying
Arnesvedonia (10): flying
Xavier, Nimm, you go!