You may want to look at what the police actually do. They don't just "patrol the schools" and go home. They actually do go on regular old get the bad guy duty as well.
"I'd like to look into it, @yourmomma, so perhaps you can provide me with a cite or two about what school resource officers do in Florida. I figured the school resource officer for an upscale suburban high school would be stationed at the school, not handling drug shootouts in sleazy neighborhoods."
You're correct about what SROs do in our part of Florida and from what I have read about Broward as well. An SRO is assigned full time to a school and spends his/her entire day at that school, not on general patrol. There are a few cases where two schools share an SRO, but the SRO is only splitting time between schools, not some school time and some general patrol time.
The gun most commonly used in school shootings (unlike handguns in other crimes) has an effective fire rate of 120 bullets per minute, and causes immensely more tisue damage than other guns. I doubt there was much time to make a difference.