From Halopedia, the Halo wiki
Beam Dance is an achievement in Halo: Spartan Strike. It is unlocked by completing Operation D, Mission 5 without being hit by a Z-510 focus turret. The achievement is worth 5 Gamerscore. It is represented by a circle with a focus turret inside it.
The achievement can be extremely frustrating, as the slightest hit will completely nullify the player's progress and force a restart. One option is to purchase the "Airstrike" armor ability which will call down a large carpet bombing in the player's immediately vicinity, allowing the player to destroy nearly all enemies on-screen - including focus turrets - without exposing themselves to focus turret fire.