After listening to Viktor and Sora's explanation, Matthew had a basic understanding of the situation. He was on the right track and now he even had allies that he could join with as they storm the enemy base. When he voiced his desire to help, Sora told him he should talk to the leader. Matthew obviously knew who was talking about.
While walking Matthew suddenly asked, "What's that smell?" Viktor started smelling his armpit and then shook his head. Sora, on the other hand, asked, "What smell are you talking about?"
"I'm not sure, but it smells like sulfur with some scent of strawberry. I really can't tell, it's just a weird smell overall."
"Oh, you're smelling my new concoction. Good thing you told me in advance." Sora took out a small vial then plugged it, making the smell a bit faint. "It must've opened when I was running away from you. Good thing you noticed, If you didn't notice, you and Viktor might have died."