The Weapons Test Engineer gets
Invulnerability every 25%, does a telegraphed AoE attack that inflicts 10 stacks of
Bleeding and moves to one of the 4 spots in the middle of the 4 walls. It may also stay where it was, as the movement is random. Bursty condition damage can be effective on this boss, as it does not cleanse conditions when going invulnerable, meaning they will still tick while it moves to the next area. Kill the boss to finish the fractal.