Responses

They were new to the dungeon and people were dying left and right. They were also getting chased by monsters so when MC fell in to a death trap, they didn't have time or luxury to check if he was still alive.
If you notice, Ryu came to MC's rescue in the skeleton field because he was more experienced by then. He had skills and weapons to have enough confidence to jump into a death field like that.
I'm at chapter 37 and I'm really enjoying it so far. The one thing that I don't fully understand yet is why is he so keen on reuniting with people who left him to die? They literally abandoned him when he needed them the most. So IDK, I just feel abit weird about that.
EDIT: I'm glad they reunited and they all seem like good people (honestly as a group they're all sweet and wholesome), but I still am baffled by how quickly they left him to die in the beginning...