Dan Allison killed himself just like it happened. What was funny was Adam re-enacted everything in the hospital room first for Matt and later for the DA. Adam came up with the theory after realizing that Dan threatened Steve as Cathy Riker overheard in the hospital. Then he found out that the vasopressor bottle was close enough to Dan that he could turn it off by himself after he shut off the monitor. Unfortunately it looks like the district attorney doesn't believe the theory. Then again Harrigan has no issue with hearing that Dan Allison hit his pregnant wife.