Nobody is a good enough shot to risk grazing someone in the head without injuring them.
Someone almost certainly tried assassinating Trump and failed. It’s shocking that it was possible, and the Secret Service has a lot to answer for if it’s true that someone was able to get on a rooftop with line of sight of a former President delivering a speech. It’s hard to express how good they are at preventing opportunities for snipers these days.
If the counter-sniper team is the group who killed the assassin, it was the first time they’ve ever had to fire their weapons outside of training.