They could have examined the outer portion of the strange structure first, wandered around the crumbling walls though there was surely only so much they'd be able to see from such antics and indeed the large archway did look somewhat intriguing as well. More awaited them to explore within the ruined building and he would give a small nod to the little man and follow behind him as he led the way through the entrance.
Inside there were indeed paths to follow, starting along the straight line they'd soon find yet more of these strange entrances, interesting in their own right though not as grand as the one they had discovered right outside. This particular one had crumbled, the doorway now half blocked and scrambling would be necessary to continue through to the collapsed room on the other side. Even Aslan's taller height couldn't see beyond the rubble to the room on the other side and he looked to Psalm to allow the other to lead again, onwards or through here?