Huh? Knight Capital lost a bunch of money, and will likely go bankrupt. Essentially, Knight's software bug transferred a bunch of money from Knight to everyone else. This poses minimal systematic risk to anyone else, and they will almost certainly get no bailout.
The markets have already recovered. The S&P was down a little bit on thurs and recovered by friday. Knight is down 60%.
http://www.google.com/finance?q=INDEXSP%3A.INX%2C+NYSE%3AKCG
This is ultimately a situation of the market being a robust and stable dynamical system.