Thanks to the metal object Alana found, Logan starts breaking the mortar all around the irregular shaped stone block. It comes away with ease, and soon Logan has cleared a good area all around the block.
Trying the block with their fingers, Logan and Johnny feel it wobbling slightly. They are now able to insert their fingers in the gap around the block to apply some strength.
The block slides forward one millimetre at a time, and to their surprise it reveals to be less thick than the rest of the wall, revealing an alcove behind it as it pops out of its place.
There is an old metal cylinder in the alcove, a little rusty. It has a screw-on cap.