When ever i log out of runescape while in middle of Dungeoneering and then log in later i am put in this room where i can go down broken stairs but then i lose everything i got is there a way to go back in without losing it all

I'm afraid there isn't. If you accidentally log out or something and you're in a group, you can go back to the group if they're still in by entering one of the names of the people in the group into your ring. If you're soloing there isn't any way yet.

thank you for your help