If you don't have an ice bath handy but you have cold packs, you can place cold packs under a persons arms in the pits, between their legs near the crotch and on their neck.
If you're working in heat (inside or out) we used to take bandanas (or old t-shirts, towels, etc), soak them in water and wrap it around your neck. Works wonders to keep your brain working and body slightly cooler.
If you stick your forearms in a tub of cool water you can cool down quick without any risk of whatever the problem is called when you cool someone down too quick.
Shock? It feels like shock is the right answer here.