I don't understand exit onto in the following sentences:
Target is east and north of you, looks like Highway 56 to 17. Will intercept him if he stays on 17. Go east on 56 off Highway 2.
You're going to exit onto Highway 56.
Does it mean the target is in Highway 56 and about to go to Highway 17, but the follower will intercept him if he goes to Highway 17, so he has to exit Highway 2 (currently he is in Highway 2) to go to Highway 56 to catch the target?
It's a part of the movie Sicario, I don't know if I can post a torrent link here.