Not worth worrying about. Bluetooth is decently secure (uses public key crypto for initial key exchange, entering the PIN at setup prevents against MITM attacks

Not worth worrying about. Bluetooth is decently secure (uses public key crypto for initial key exchange, entering the PIN at setup prevents against MITM attacks, and the range is short enough anyway you don't actually have that many possible attackers). If someone in your office cared about what you're typing, they'd simply spy on you visually, with either their eyes or a camera. Or install a keylogger, if it's their device.