I see where Merii's constant disbelief comes, but it needs to start at some point if this professor is just another asshole with some fucked up intentions it can be dealt with when the time comes, but the necessity and curiosity to understand the demons abilities won't just go away.
Merii apart, just Lorem ability to generate unreal quantities of heat has already the possibility to resolve energy problem in the world and who knows what more.
The important thing here is... Merii is right to uncomfortable and suspicious but just because her experiences were bad doesn't mean all those that study demons are just bad people, we need to see where this will go in the end.