Someones theory and makes some sense. He could hide the 2 9mms(if true) very easy. I heard only one got shot in the dorm before the pause. Their theory was he went to the dorm looking for his target and he/she wasn't there. While pd was tied up with other shooting with maybe little to no witnesses due to the hour suspect traveled to where he knew his intended target would be and waited. Once there the massacre is still a mystery.

Again this was one of the so called experts theory and not my own. It does make a little sense as to why he would have waited the time for the other incident.