Did the MC know this guy was evil beforehand? Because it seems like it was common knowledge throughout the guild they're working with. And if so, why did they ever tell him the location to his lab to being with?
@Baysiri exactly but i think so he could have an excuse to go out of town or maybe so he could get scroll as he was guarding/blocking anyone from using the gate but last chapter he should have detroyed the body aftre all he can't kill the mc in the other body also i just looked back and maybe the glass was made up of a strong material