My alarm goes off while on a phone call. This is ridiculous -- how do I turn this feature off?

I'm a long time Google phone user and got used to many of its features, including the silent warning notification of an upcoming alarm and the ability to turn it off. The iPhone is severely lacking in this area. Not only is there not a silent notification about upcoming alarms, but the alarm goes off *during* phone calls... While I'm holding the phone to my ear. And the person on the other end of the call can hear it. I use my alarm for several things throughout the day and it's incredibly embarrassing when I'm on the phone with a client and my phone alarm goes off.

Honestly, I've had the iPhone for almost two years and I still miss my Google phone every day. I plan to switch back at the end of my current contract. I like iPhone's security and product quality; I wish they would take the time to provide basic features.