The Kamchatka Peninsula is in north-eastern Asia and Venzuela is on the northern end of South America. It's not like he's giving an address, it's a pretty big slice of the earth he's pointing out.

Asteroids usually have huge relative velocities to earth, passing by in minutes or even seconds. This means that even if you only know where it's going approximately you'd know which way the earth would be facing from rotation and the angle of approach.

The probable location of impact (if there is one) is simply based of which side of the earth will be pointing at it as it passes (or doesn't).