The bst 4 Team Slayer spots at Lockout are:

The Weakener
The bridge to Library and Center BR. There, you can kill all the n00bs underglass and at least tell your teammates

The Leader'
BR3( Top BR Tower) There, with your team's best sniper, you can get all the action from the Lift and Sniper Tower.

The Scraper
The stairs from under glass to top BR ( facing the Lift) There, hidden, you can shower uponthe Lift and pick up scraps on under glass.

Maintenence
Basically, this person just checks up on everybody, making sure they get the job done right. They pick up scraps and help all other positions.