It’s 2nd block, and my students begin to file in. I read the reminders scribbled on Post-It notes around my computer: A fire drill is scheduled for today. I know it can’t happen during lunch, and the weather forecast called for temperatures in the high 80’s later in the day, nixing 4th block as well. A fire drill will most likely happen during this block. As my students take their seats and begin the warm-up activity, I quickly consider how to rearrange my lesson plan. What’s most important? The fire alarm sounds, interrupting my internal debate.