Despite the 100,000 XMR dump the value is actually slightly up today in terms of $ USD due to the rise in Bitcoin. Just as a general observation, in the past when BTC has gone up or down I have noticed that XMR/BTC has gone opposite on low volume so that the USD value of XMR has stayed about the same within fractions of a cent. There must be bots that try to take advantage of rises or falls in Bitcoin by getting in or out during volatility. Either way I would have speculated that there would be selling pressure today to keep XMR in the $0.42-$0.43 range regardless of that dump.