"Place that material over there, it's not that important to be in front of Walker, it just needs to be nearby." Gil's directions were in direct communication with what Walker wanted. He had explained what to do with which materials before they arrived.
The only issue was that when the people came to deliver them, they brought with them their own mana. Everyone radiated some mana, it was inevitable. Without the highest control of mana within their own body, their mana would seep out causing them to leave mana behind.
In turn, that mana would be absorbed by the partial natural rune causing damage to the process which Walker Was trying to control. If he lost focus at this point while talking to someone, then there would be issues with the partial rune most likely causing the mana it was made of to shoot out damaging the areaa massively. Hence why Gil was in charge right now.
