they both had to laugh, because they know that unknown, the monsters, the running is the best part. No chance is either of them going to give that up. No way they're just going to ignore whatever is going on here.
"They're screwdrivers! What are you going to do? Assemble a cabinet at them?"- 8 1/2 Doctor. "Who looks at a screwdriver and thinks oooh, this could be a little more sonic!?"- Jack. "What? You've never been bored? Never had a long night? Never had a lot of cabinets to put up?"- Nine.