The holy grail of the BEEP(1400, 0.08) command: USB-HID

[gehakte_bits]

Some civilized ways to break out of a Prime and generate on-demand-audio-requests are:
- screen (camera/light sensor)
- RF interference
- USB-HID USBSend() command to a proper audio device (MP3/GPIO-Piezo)

If one is not interested in an I2C interface or an UART for its intended purpose, then the USBSend(data)->USB-HID->UART TX-data (passive piezo), or its TX_Active pin (active piezo), can drive a piezo (at 3.3v, max 4mA, sounds like a bb.hamster in distress). Some amplifier/transistor to a piezo can enhance the audio: they typically require more than the output current of those pins.

If the Arduino can act as an I2C slave it probably could be programmed to forward any of its data.