I had a rather unsettling experience today on a Mad Dog flight from DFW to BWI....Firstly, the flight was over 2 hours late because the aircraft scheduled for that flight never left Oak City due to a mechanical...had to wait on a replacement plane. AA used an aircraft that arrived from DEN for this flight. The routing was a bit strange too...up through STL to avoid weather. But that wasn't the unsettling part...As anyone knows that has sat in F on an MD8X, you can hear what is commonly referred to in the industry as the "Bitch Box" (sorry ladies) calling out the altitude from 2,500, 1000, 100, 90, etc. What the BB also does is call out emergency situations such as stall warnings, and landing gear issues. Upon approach to BWI, the BB starting calling out altitude and when the landing gear was deployed, the BB siren went off and the synthetic voice said Landing Gear, repeatedly...siren, the landing gear. The FA leaned his head over to the cockpit door and he and I locked eyes with a little panic involved! Then, the gear was retracted and re-deployed, and again, the siren and the voice, Landing Gear, repeatedly...what was struck me as really odd was the pilot's decision to land the plane with the warnings going off non-stop! I will say it was the smoothest landing I have ever experienced, and there was little to no braking for quite a while, although the thrust reversers were screaming...happy to say the gear did not collapse but still quite concerned they made a decision to land the plane with the warning siren and BB calling out an emergency!