You know the swat team would be driving > 100mph
just because they could, LOL
An attack in the morning may coincide with rush hour traffic. It would be a challenge for a land vehicle to get anywhere fast. A helicopter becomes a much better choice.
A five minute response time is possible only if you count a few Sheriff's deputies who will arrive but wouldn't be able to do much. An active shooter in an average school building may require twenty or thirty LEOs to secure. Some would be outside, forming the perimeter; other go inside in pairs and check every room and every broom closet. If students are present, there will be hundreds of them; that will be a distraction too, and the shooter may be hiding among them.
To be honest, I can't even say for sure that Howard County even HAS a SWAT team.