Man in the middle attack on SSL in real time is extremely hard to pull off.. that's the whole point of using SSL that all that anyone who hacks the connection between the tower and your phone, your service provider and the tower and google server would see is an encrypted stream of data, as the encryption is happening between Google and your phone in the application layer. So while it might increase the attack vectors, it is unlikely to make any change in the security of your overall connection. It is much more likely that someone hacks your computer, installs a keylogger and steals your password.