Operation Hard-boiled. Joint game (Call of Duty: Modern Warfare (2019))

How do I complete a 4/6 point?
"Make triple murders in slip by selecting Alice as her demon dog performer in any joint operation: 10"
I don't know how to do it. Took a shotgun new JAKS 12 (aka AA-12), went to operation Seif, there are the opponents of the gurgling basement, but the time of slip is so small that I manage to kill only 2. Or a shotgun shoots slowly ((((