Salvation Shield Mechanics

By The_Shaman, in Rogue Trader Rules Questions

Hi, I was arguing with a player in my game just how the salvation shield works. In "Into the Storm," it is stated that the device "generates a silent, invisible field of roughly one square metre,projecting outward half a metre. "

As I understand that, it projects a fixed "shield" in one direction,not an omnidirectional screen.In which case, it cannot defend from attacks from all angles at the same time. How should that work mechanically - does the field not function against, say,an enemy attacking a character from the rear and should a character use a reaction to realign the shield to protect a different angle?