>>723294484
The same way she manifested the Otherworld in a random ass mall miles away from Silent Hill.
Hax.
No, seriously. The japanese guidebook for Silent Hill 3 says she has a special power, and that's how that happens. She magically impregnates Heather, calls in the Otherworld to stir up baby "god" and fucks off for a while. It's Claudia's otherworld. It then gets mixed with Alessa as her memory resurfaces.