Beware!

'If it thinks hard enough, the mental barrier will shatter,' Liam realized. 

It was a sad realization. 

Not because the monster was going to die, of course.

But because Liam was not going to extract as much information out of it.

Life was tough. Deal with it.

Liam couldn't ask any big question. Obviously there was a limit on how much info the monster/human had in the first place. 

He couldn't ask how it knew the Echorian language.

He couldn't ask where his origins were from.

He couldn't ask for anything specific about the Tomb, either.

'It probably doesn't know anything about these rooms.'

For example, asking for how many rooms the Tomb had, or the most efficient and safe route to clearing it, was stupid. There was an abysmal chance of it knowing such a thing, and even if it did, why would it tell Liam?

Right. The monster still had "free will". It could just choose to kill itself.