A modern day equivalent of a run on the bank?

Granted, the Fed's intervention to avoid the total collapse of Bear Stearns is not exactly analogous to saving an institution from the threat of a bank run if we consider the precise definition of a run on the bank, i.e. a situation in which panicked customers simultaneously withdraw their savings as a result of fear that by not doing so they may lose what they have. As the bank only keeps a fraction of deposits in cash, without some type of external help, it will implode.
Bear Stearns is not a commercial bank and therefore technically does not have any deposits to raid. In Bear's case the crisis began when their ability to borrow was suddenly cut off. It ensued the collapse of Carlyle Group's flagship Carlyle Capital fund when rumors began to circulate that Bear had a large stake in the fund. So why, you may ask, would this be considered the modern day equivalent of a run on the bank, warranting Fed intervention? The answer has to do with the bigger picture. The Fed figured that the risk of triggering systemic risk by allowing Bear to go bankrupt was higher than the risk and repercussions of moral hazard. It would have led to further casualties in the financial sector as lenders became more reluctant. In addition to coming to the rescue of Bear Stearns, the Federal Reserve announced that it would extend its lending facilities to a wider segment of the financial sector. This should help substantially to mitigate the risk of another blowup.
As for market conditions, the rough ride is likely to persist as the root housing crisis will drag on for a while to come irrespective of what the Fed and/or government do.