I don't think Dennis Allen has the authority to fire anyone. This is all Loomis. Look at it from the perspective of Loomis runs the ship and everything makes sense. Loomis needs Allen as the coach because Allen is a beta and will let Loomis do it. You can't bring in a Pederson type coach because he wants too much control.
In Loomis's interviews, he still sticks up for Carmichael. So he's not going anywhere over the bye but he'll be their sacrificial lamb that gets fired over the off-season to save Allen's job. We won't bring in any new outside OC either, they'll just promote Curry.