The really really stupid thing here on the NFL/Testers behalf is all they needed to do was throw out his initial test and have him re-test once he got re-hydrated (usually an hour and a 16 oz. cup of water later).
Unless there is a specific item in their testing procedures that says they don't have to follow a chain of custody (the cup you pee in is the one we have to use), or there is a specific section that says they can not retest you within X amount of hours or days, then it makes absolutely no sense that the tester wouldn't have said "ooops... broken cup, let's retest in an hour. Here's a glass of water. Have a seat and watch some tube or goof around with your phone, and let me know when you're ready to do it again."
I have had a "chain of custody" situation happen before at pain management when they forgot to empty the storage bin you put them in as they got backed up because they were busy. There were multiple unsealed cups and somebody had forgotten to take 3 out when I put mine in. I pointed out when I came out (it's a pass through door that you can put the test in on your side, and the nurse pulls it out from the other). I said that there were multiple cups in there and there was piss all over the place (looked like somebody intentionally splashed all over the place... probably to try to taint all tests and cover themselves for using street drugs) and I was uncomfortable (they were using dixie cups with our names written on them by us). I said I wasn't comfortable with the whole situation. They said that it was their fault and they'd retest me another time. The next time I was tested, they used sealed cups with my info pre-printed on a label by a computer with a permanent seal on the cup that I had to break, and every time since I've had an empty pass through to place the cup in.
R.I.P. Dad. I miss you. You will never be forgotten
1/12/39 - 8/7/08