They knew that whoever was there to do it, most likely Ethos himself. Would have had to physically be on the island.
Which meant he had an easy target on his back while he was doing it. They couldn't exactly hide the temple and what they were doing especially if they wanted to do the process quickly.
To do that, Kurt, Odin, and Elizabeth would break through and take the top of the island, leaving everyone else to handle the defensive formations around it.
What made Avalon a bit unique was the tether that had been created. In other words, upon a large plate, some old god had made a ring and attached a stairway from Avalon to the plateau. And from then on the island would spin around it. Or rather loaf around as they all did.
Kurt wasn't sure how the staircase was reforming itself to account for the movements. But it always seemed to be sturdy.
