The pharmacist described the location of an underground shop. Viny went to another pharmacist. He took 50 antidotes from there, too. Then he got the location of same underground shop from there.
Viny returned to the hotel. After watching Jenna's method in their room for a while, he picked up an Ufa Devil's heart. He poured a sip of alcohol over the heart. Then he shredded an antidote into powder and poured it on it.
In a single breath of time, the heart of Ufa Devil completely dried up. Viny got angry and did the same experiment with the antidote he bought from the other pharmacist and the drink the other bartender gave him. The same thing happened again.
Viny thought something fishy was going in this. The whole city could be fooling newcomers in this way. Or, much more dangerous, could the whole city be working for another agent who became the lord of the quest area?