The Seventh Gym Leader is Clair, the Dragon-type Gym Leader in Blackthorn City. While there are ice-type Pokemon in the gym, there is no ice door to contend with.
To get past the Seventh Gym in SoulSilver, you need to defeat Clair and her Dragon-type Pokemon, using strong Fire, Ice, or Dragon-type Pokemon.
If you're having trouble defeating Clair, consider:
* Training your Pokemon: Make sure your Pokemon are strong enough to handle Clair's Dragon-type Pokemon.
* Using type advantages: Fire, Ice, and Dragon-type moves are super effective against Dragon-type Pokemon.
* Using strategy: Pay attention to Clair's Pokemon and choose your attacks carefully.
Good luck defeating Clair and claiming your seventh badge!