So he chose to not commit a penalty by taking him down nnd that momentary lapse of unreason cost him a sack.
FWIW Doc - I was curious so I took a look at the stats for the dirty fish N. Suh. It appears he is trying to clean up his act.
http://www.nflpenalties.com/team/miami-dolphins?year=2015&view=players
Neutral Zone Infraction (3), Defensive Offside (2) -
http://www.nflpenalties.com/team/detroit-lions?year=2014&view=players
Defensive Offside (4), Roughing the Passer (1), Face Mask (15 Yards) (1), Encroachment (1)
http://www.nflpenalties.com/team/detroit-lions?year=2013&view=players
Neutral Zone Infraction (2), Defensive Holding (1), Encroachment (1), Defensive Offside (1), Tripping (1), Low Block (1)