Two Cechan's with an accomplice and perhaps more murdered 3 people, a police officer and injured dozens. This is a significant criminal activity.
Keeping perspective is important though. Within a few days the police have apprehended an accomplice, killed one of the perpetrators and are in pursuit of the other.
Shutting down Boston in order to apprehend one man is a significant overreach. Boston generates $800 Million a day. It is unclear that any lives are even at risk.
Government, specifically the Mayor and Governor, is protecting itself, not the citizens of the community, who would surely be better off risking another death in the chase in order to pursue their lives and livelihood for the day.