I know what you mean. I live about 35 miles from my school, travel by train, the area is below the waterline and there's a nuclear plant near the area...go figure!

Anyhow, I have put a small tin into my school-backpack (no locker unfortunately) with:

2 Energy-bars
1 small candle
1 box of wind/waterproof matches
aprox. €100,- cash
1 small flashlight
4AA batteries
1 pair of earplugs
2 lightsticks
1 small map of the area

Other stuff I've got in the school-backpack:

- 2 water bottle that I drink during the day
- small crowbar
- 2 n95 masks
- pair of work-gloves
- 5m. paracord
- CPR-kit
- survival-bag (also handy for protecting your backpack in the rain

This is carried in addition to my EDC:

-Keychain (Leatherman Squirt, folding scissors, tweezers, photon II)
- Fenix L1D-CE flashlight + extra batterie
- 2 hankerchiffs
- Benchmade Griptillian (not at school)

Jacket:

- PSP
- FAK
- CPR-kit
- Wallet with €50,- emergency cash, ID, BCB survival-tool and pocket-sharpener
- Cell-phone
- Space-blanket
- 2 pairs of nitrile gloves
- EMT-sheers
- triangulair bandage with quick-dressing no1

Seems like a lot... it is...untill you need it..