Pedestrian struck 400 yards from fire station, fire department and EMS show up in force...20 minutes later

This evening, a female pedestrian was struck at the intersection of Longwood Avenue and Huntington Avenue by a hit-and-run driver. Waiting for the T, I saw the aftermath; a MassArt campus police car blocked one lane while the victim, hidden behind the jersey barrier and about 10-20 feet away from the crosswalk, lay on the ground. A young man was possibly an acquaintance. Someone offered their jacket, which was welcomed. A young woman in scrubs appeared to look her over/speak to her.

I started watching the clock when I realized it had been a while and there were no signs of ambulances. After several minutes, someone's nearby campus police radio squawked, "did someone call 911?", and it sounded like (but I'm not positive) someone replied, "yes, at 6:25PM"; it was well after 6:30. At least ten more minutes went by. Finally, from the firehouse just down the street came sirens and Ladder 26 and Truck 37 arrived- a total trip of at most 30 seconds. A Boston EMS ambulance arrived a minute or so later, but wasn't able to park close to the victim because Ladder 26 parked slightly down the road from the victim, and Engine 37 blocked the remaining free lane of traffic.

I asked a bystander if it seemed like they took a while to respond, and he said "Yup. She's been lying there for about 20 minutes." He shook his head and walked away. Two campus security guards/policemen jovially greeted each other right next to me, high-fiving each other, and one laughed and said "Yeah, they must be REAL busy tonight."

Aside from being a shameful failure of Boston's emergency services, maybe someone from Boston Fire Department can explain why two fire trucks (one of them a ladder truck) need to respond in addition to an ambulance? It's a practice the Boston Globe has called into question before, noting that medical calls make up almost 40% of Boston Fire Department's runs now. Aside from clogging the scene with extra vehicles and personnel, doesn't tying up units like this hurt our precious fire coverage?