An expert makes a move, and you know if there are any.
The assault team split into two columns of six each, with the lead person holding a transparent ballistic shield and the rest forming a single-file line closely behind, attacking into the room; this was the most common tactic in a siege.
However, this tactic assumed that the enemy didn't have heavy weapons or heavy firepower.
Now two people had been shot, not because their shields had been penetrated, but because they hadn't stayed close to the person in front of them as the tactical drill required. Their movements were a bit slack, and their formation was loose, allowing someone to seize the opportunity and hit them in their exposed spots.
This serious issue meant that the assault team was on the move and not at full speed, plus the targets were small and fleeting. But the shooter had nailed two people with just two shots, using a pistol— that could only mean the shooter was an expert, a very, very formidable one at that.