Iapetus shall give Sinmore an apologetic bow. "I apologize, Maga. I do not have the skill to assist you in this. It is something I shall... sooner or later... correct." In fact, Iapetus seems to be badly hiding a bit of upset that he can't help in this case.
Upon entering the hillside, Iapetus looks about the dark tunnel-space, peering down both of the side passages. A moment of silence to see if there is audible activity down any of the tunnels, then, "Creo Ignem," he chants, summoning a globe of firelight in his hand (Spontaneous CrIg 5 Palm of Flame, probably needing to fatigue himself because he never actually learned the formulaic spell). Before going any deeper, the Spanish Magus takes a moment to ensure his (now blonde) hair is securely not in his face, and his mace is securely held in his grip. He chews for a moment at his lip before speaking to his companion. "Sodales, you are one more familiar with this Vis source than myself. Would you know which direction to go?"
Having had to be quite magically spontaneous, Iapetus is going to lean against the wall of the tunnel and try to catch his breath while he has a moment. Phew.