Even elder Stark felt the same immense shock when he arrived there. The entire Spar Arena was now surrounded by deep trenches, lots of traps and defensive arrays that turned the entire place into a fortress.
Richard's side tried their best to infiltrate through such fortifications, ending up losing many masters just to claim little space. When elder Stark arrived, and after he passed his shock, he realised why Lara dared to do that crazy move.
She wasn't idly waiting here to get surrounded and attacked. When he saw such a defensive measure filling the entire place around, he knew this war wasn't lost, not yet.
Anyone on Lara's side seeing this got their moral skyrocket again. Everyone thought about the dark future of their family, thought about the inescapable fate of losing their leader. But when they saw this scene, they all knew there was still hope.