TSA is inconsistent
You did err when you gave TSA your key. ONLY YOU should EVER have your key, per Federal law. You unlock it for them, and when they're satisfied you relock it and you keep the key. That's the law.
I've written TSA about this, to clarify what appears to be an inconsistency in how TSA operates and what the Regulations state. Their response quoted the relevant portions of Federal law, then went on to state a completely different set of procedures
(namely: surrender my key and wait, upwards of an hour, for my key to be returned to me - OK, they didn't say all of that but that tends to be what happens. The waiting). I've taken about eight trips with firearms, and there are different procedures at different airports, and even between different agents at the same airport.
If you're going to fly, know the law and be prepared to stand your ground as to what is legal or illegal, AS WELL AS what each airline requires or permits, with respect to ticketing or other airline personnel. I've had some wacky and daft "requirements" quoted to me by well-intentioned but ignorant ticketing agents (in the end, TSA or supervisors over-rode what those agents were telling me). However, you are not likely to get anywhere arguing with TSA. It is their way or the highway (literally, you won't be taking an airway), regardless of what the regs state.
On one leg of a trip I almost missed my flight trying to push the I-need-to-maintain-control-of-the-key-at-all-times requirement. I arrived three hours prior to my departure and the airport was empty, but I nearly missed my flight thanks to TSA, the Regs and my own stubborness. Ultimately I surrendered my key and waited, gun case out of sight for 30 minutes until I received my key back and an "OK" to board. My sprint to the gate concluding with the plane being pushed back from the gate as I buckled in to my seat...
While that experience was the worst I've had, TSA has never permitted me to even touch my gun or case once they begin their inspection. For me, the inspection process has varied from being conducted within sight, rapidly, to being done out of sight and taking nearly an hour in one case. They always take the key and handle the locks. The key is returned only after my case has been whisked away. Do you guys have different experiences?
When I fly with firearms I arrrive early to allow for possible delays in the checking process. I know the law and the airline requirements, and generally speaking don't argue with TSA. I view two hours prior to departure as the minimum (cutting it close), with three hours a safe margin. Your airport may differ.
2KYDS