You are correct about the last line, there is a great game in Russia's mind, no doubt about it. Also, no such thing as " at the cost of India" or anyone for that matter. Modern day politics and alliances are not built at the cost of each other. Its strategic interest combined with business and profitability.
Russia is trying to be a weapons exporter like the US. They sold you SU's and Mig-29's, they sold SU's (and some models with TOT) to these Chinese. Similarly, what makes you think that they won't sell Pakistan anything else outside of these Choppers???? I think there is a LOT more to come.
The Russians are also very smart. They can see through the Indian game. They know that India is their customer (at a larger scale) for another ten years and then it'll be like "hey man, good to see you" type of a deal. So, they will open up their arms market to Pakistan. Read this and write today's date down. In the next 5 years or so, you'll see more defense agreements between the Russians and the Pakistanis (plus add China to the mix). Just like you said, this is a small step towards a huge block.
Also, you can't blame them. The US sells Israel all kinds of weapons. But then it sells weapons to the Arab states also.......why do you think the Russians won't do it, specially when India went pro-west already and Russia can use another weapons buyer and a strategically located country.....by making friends with Pakistan, they can in the future, potentially avoid any issues from Afghanistan's end from the West or secure their borders from this end. The other side is China and Iran, so they already enjoy warm relations with them. Very long term planning indeed with this move.