Very interesting epsode, and pretty intense for "Grey's."
I wish the script had ben just a little more believable .... after the shooter gets shot by a SWAT cop that's apparently 20 or 30 feet away, and not likely all by himself, the shooter is then able to visit a number of other locations around the hospital, over the span of many more minutes, without another cop anywhere in sight. This aspect was totally not believable.