[MrTerrorist]

Spoiler for ch112-113:

The weird guy happens to be one of their science teacher's who happens to be a perv and mad scientist but ch112 was mostly fanservice with Ryouchi thinking pervert thoughts of the girls while Akira got into some perverted moments with Oomori.

Anyway, in ch113, the group finally arrives at the pyramid. To scout the area first, Akira and Ryouchi go to the camp first pretending they are alone while the others watching from a hill. The two of them finally meet the Doctor which everyone at camp are afraid of and have been forced to dig around the pyramid. The Doctor asks them a favor to go through a tunnel under the pyramid.