Im curious as to the possible responses to an incoming phone call .
imagine if your phone rang while you were on approach at night.......would you take 4 seconds to ascertain that it was the PHONE and not the GPWS ?
or would you just instantly firewall the thing then pull it to idle and resume the approach when you realised it was the phone ?
either way , sounds like a recipe for skidmarks followed by coffee with BASI.