It’s only a short amount of time, but Roy Keane doesn’t need a lot of time to scare you shitless with just a glance.
Ask this linesman:
Roy was out promoting his latest book when the unfortunate reporter’s phone started going off. What led was the type of stare you give when you see some knobhead try to hit on your girl.
Keane has a little history with phones going off during conferences, the last time he dealt with it a bit more brilliantly though.