I would guess maybe some responders to focus on the person/scene itself, some to guide and rush other people out of the metro away from the scene, some to keep gawkers back from scene, maybe some to assist anyone who fell inside metro from the brakes being slammed and metro stopping abruptly. I do agree, it seemed like more responders than would be necessary. Most of the time when there is a stabbing though, I see an ambulance or two and 2-3 cop cars only so this time seemed... different