The reaction to Dave's declaration was surprisingly positive.
"Brave Dave's got a point," Pen said in response. Dave smiled and then looked around. The receptionist had left, leaving the lobby completely empty. "So everyone's who's game - follow me!" 
Dave, having come up with the idea, followed right behind Pen up the stairwell. The mood seemed to lighten considerably as the prospect of looking at boring rocks was smashed to bits, much like rocks themselves. 

"And if you're not game, you still might as well follow. You're gonna get in trouble anyway for splitting up from your group!" Pen called down to those who had stayed behind, who quickly clambered up the staircase behind them. The staircase continued to curve upward, the light from the lobby downstairs fading fairly quickly. The walls and wood of the stairs were in disrepair, with paint peeling and dust nearly everywhere. Dave sneezed. Pen stopped in front of him as an old, wooden door blocked their path. He sighed audibly. It was probably going to be locked. He was pleasantly surprised as the handle gave in and the door creaked open, revealing a stark white hallway, complete with fluorescent lights overhead and a squeaky (literally) clean linoleum tile floor. Dave stepped through the door, looking around. Machines were rumbling along somewhere, and the lights overhead buzzed incessantly, but otherwise it was deathly quiet. Pen started walking forward once more, with Dave following behind. He felt uneasy about the entire place; he suspected it was not a rock research center as advertised. 

As the group neared a corner, Dave heard voices coming from the end of the hallway. He peered down, and saw a nervous-looking man in a lab coat knock on a door, wringing his hands. When the door opened, he began speaking quickly to whoever was inside, about what Dave could not hear. The nervous one nodded and began walking to where the group was, a team of several scientists following him. Dave exhaled quickly and threw one of his arms behind himself, breathing quietly, hoping none of the scientists or the nervous-looking man came to where they were hiding. When he heard their footsteps fade away into an adjacent hallway, Dave breathed a sigh of relief. He turned to the group.
"Sorry about that, some of those scientist guys were comin' to where we were," he explained, rubbing the back of his head. "Didn't want anyone to jump out and get us caught." He peered down the hallway, and saw there was nobody coming. 
"Coast is clear," he announced, walking forward.