It didn't take the group that was left to fight Hunter in the room up to a minute before they could end Hunter.
Hunter had repaired his machining backpack, so, initially, he was able to move around, stretching long metallic legs out to propel himself up.
When he evaded their attacks, he placed his hand on the earbud in his ear, clicking a button on it.
"Masterpiece, get back here!"
Hunter smiled saying that. He thought he had gotten Ryder to get his command, and he was expecting Ryder to be there any moment from then.
"I should hold out for about fifteen minutes, Masterpiece should be back by then," He mumbled to himself.
Before he knew what was going on, Oscar kicked the robotic leg, and it broke.
Before they could attack the second one, Hunter let it back into the backpack, hanging himself on one of the metals on the roof of that room, he waited for Ryder to arrive.