For one thing, the front entrance is trapped, the stairs are trapped, and those are pieces of information that the paladins and Sophia have definitely been given that would be good to tell everyone else.

The backstory of the ruin may also give everyone a better idea of what to expect from the untouched levels as well.

At the very least we need to do the explanation while on the way there if not before we start travelling, so if someone suggests that IC we can do that. But wandering in there without any briefing beforehand is a bad idea.