Drawbridge Key
From WikiRaider
The Drawbridge Key is a key item found in the level Tibetan Foothills, in Tomb Raider II.
It is found upon a pedestal below the snowball hill area past the snowmobile big jump. It is guarded by a lone mercenary.
It raises the Drawbridge in another ice chamber, and allows Lara to cross to the area of the snowballs, and then start an avalanche, which then provides access to the Hut Key.