Maybe its an egg room. Where he studies pokemon eggs.
Since that was what begins your journey it fits in.
I think I have a theory. Elm probably has a room upstairs where he studies the eggs, so he is probably studying about the eggs while Silver is stealing a Pokemon from his downstairs lab. That is why Elm gives his aide the egg to the player early on in the game. Later on, I'm not sure if he's going to give the player another egg, or if he's going to give a Hoenn starter? I'm assuming that he is going to instead give us a Kanto starter because Gamefreak is probably almost done with the fifth gen and might be making remakes of Ruby and of Sapphire.
This idea is probably, along with a lot of other ideas. I think it is definitely a way of following the manga a bit more and making more sense on how Silver got to steal one of the starters. Though, if it is an egg lab, then I don't know how it can be an egg of one of the starters. The reason why is because there are three, and if it is one of the other Odd Eggs, then it'll be disappointing, as not everyone will get the starter they may want. Anyway, these are just basic speculations, we'll end up finding out sooner or later as news of the game begins to explore more within detail and storyline.
Maybe the eggs are like in the anime ,with each egg having different patterns depending on the Pokemon that's within. I think that Elm will let us choose what egg we can have after the National Dex is acquired, so we could be able to choose which Pokemon we want because of the unique colors and patterns associated with that specific species.
I think that once we get into Kanto that we are going to get Kanto starters and once we defeat the Elite 4 there, then maybe Hoenn starters.
what pic are you talking about
oh that pic... well how do you know its his lab nintendo sed it was just a screenshot?
well the houses down below are new and how do u no that silva
An attic, possibly filled with appliances for Rotom to posses to access his froms in HG/SS. Or a decorative storage area with a few Items slightly useful at the beginning of the game, like a potion or a berry.