Arvell turned to his team and thought of warning them, but he didn't have any conclusive proof that he could share to prove that something was watching them.
He also couldn't just state that his observational skills had reached the level of detecting killing intent that clearly, since noticing a trace of killing intent that small was an impossible achievement for someone his age.
Much to the point where his group would not even believe him anyways.
The only thing he could really do was just formulate countermeasures on his own to defend himself and his group.
While he didn't particularly care much for Marisa and Julius, he didn't want Lillianna to get hurt.
Something like that would definitely leave a sour taste in his mouth.
After progressing down the tunnel for a few minutes, Arvell's group encountered a couple of beasts, but considering just how strong their group was, it was almost a synch to take them out.