Objective: Find a way down into the archives
As soon as you reach the far side of the crack, your objectives will be updated. There is a new Base Camp ‘Chamber of Records’ here and a Mural [01/03 - Greek] on the wall behind it. You can use the Base Camp here to apply any upgrades you require and spend any skill points you have. Exit the Base Camp menu when you are ready to continue.
Use the exit provided and follow the path downwards until Lara points out a stack of vessels filled with Greek Fire on the path ahead. Grab the quiver of Arrows propped up against the wall on the right if required, back away up the tunnel a little and shoot the vessels to blow open a passageway.