A few years back I fell pretty bad on my bike (mountainbiking down hill and slid off the narrow path into the undergrowth). Tore a 20 cm long gap from knee to the ankle. Having shorts on, I could see the blood bursting out every heartbeat (surprisingly low due to shock or surprise). Fumbled with the first aid kit from my pannier back (easily accessed in a side pocket), the kit open, the Celox pack from there and bit my lip when trying to open it. Probably inhaled half the stuff when the package finally tore. Poured the rest on the wound (probably incorrectly, didn't remember to read the instructions). The blood flow was sufficient to drain what little Celox there was away from the wound to coagulate on the back of my shin (hurts like hell when you pull it off, it sticks well enough to take half the hairs off too).
By this time I was shaking, although didn't realise it at the time. Managed to open a roll of gauze and press that against the biggest source of bleeding. A few minutes later a friend reached me, and found a punch of butterfly sutures from my kit and put those on and retied the gauze.
My friend later told me I was mumbling incoherent words repeatedly and explained that I need to fetch some water (for what, don't know. Had a almost full camelpak on me still) about half an hour before "snapping out of it". I remember being surprised my friend was there, so some blackout/phasing out happened.
I suspect I might have not managed to apply more Celox even if I had it, and the first patch didn't go that well either.
Got to a hospital some six hours later, where they cleaned the wound and redressed it. Gave me a 3 day course of antibiotics and a 20-pack of codeine for the pain and sent me home, so obviously not that bad a wound.
I don't carry Celox any more when cycling or pack packing (but do have the few sachets in my home medicine cabinet), figured it wasn't worth the money, although I did read the instructions afterwards and asked the doctor about it who explained it's proper usage pretty well.
-jh