"Wait!" Eleria calls out to Elthic. Perhaps a little too loud, the strain in her voice obvious.
"I don't know what it is, but there is some kind of magic beyond that barrier. And it's substantial. It could be a trap. Or a ward. Or it could be something else altogether."
She reflexively draws her bow and nocks an arrow in case of any threat as she backs off a little [30' from door] and also surveys how difficult it would be to use the collapsing staircase as a possible means of exit from the basement.