The players did end up getting set before the kick, but with his coaches yelling at him that the players weren't set, and there only being a few seconds on the play clock, he didn't have time to stop, focus, and look at every player carefully and then make a decision. All he had time to do was trust what he was being told and act. Besides, statistics show that there is virtually no impact from icing anyway.
Below is some stats I found in a Sporting News article.
Over the past nine years, Tobias Moskowitz found that when an opposing coach iced the kicker as he attempted a clutch field goal, those kickers actually became more accurate.
Time on the clock --- Iced --- Not iced
1:59 to 1:01 ----- 74.2% 77.6%
1:00 to 0:31 ----- 74.3% 74.6%
0:31 to 0:16 ----- 76.0% 76.9%
0:15 to 0:10 ----- 77.5% 75.4%