It took Andrei a while to sneak out from the castle, but he knew it was definitely going to be worth it. He wasn't the type to have signed consents from his parents that he may leave the castle for a certain amount of time. Not that he doubted his parents would sign it at all, but the whole process was pointless and tiresome to him. Besides, the consent form only allowed him to go to Hogsmead. Which again was of no use to him. So then he decided not to get it at all. What was the point anyway if he was going to go somewhere he wasn't suppose to.
The risk he was taking by going to this store was more than worth it. In here, he literally felt like he was in heaven. His own, specially custom made for him heaven that is. He could find anything that he was interested in and had been wanting to try out for a while. New things and products came out very often in this store, so there was always something new to see. Definitely this was a place he couldn't miss out on. Many of the things they were selling he had tried to construct himself, and successfully so. But with some he had a bit trouble, as they were more demanding. While on others, he tried only to fail in a large fashion such as an explosion or a poisoning.
He diligently observed the new kind of puking potion that just came out. Reading the ingredients on the back, he wondered in what percentage would all of those things be and he tried to figure out the most probable formula in his head. Perhaps he could even replicate it at Hogwarts, with enough work and patience of course.