Q: siri is on my screen is locked and i can't unlock my iPhone

Howdy Kavah,

If you cant unlock your screen and it seems unresponsive, I would reset the phone.

Resetting your device

Press and hold the Sleep/Wake button and the Home button together for at least ten seconds, until the Apple logo appears.

From: iPhone, iPad, iPod touch: Turning off and on (restarting) and resetting

          http://support.apple.com/kb/ht1430

You can also disable Siri if you wish:

Settings > General > Siri.

 

From: iOS: About Siri

          http://support.apple.com/kb/HT4992

All the best,

Sterling