Soros did not do anything, at that time, Southeast asia currency and stocks were way overvalued, that's why shorting worked. Hong Kong dollar was also at least 10% overvalued, but Chinese and Hong Kong government sold a lot of dollar to keep the peg, actually hurted Hong Kong economy. The famous Pound dePeg which netted Soros 1 billion also helped Britain Economy. Soros is basically a value trader.