Andrew had a feeling that Maxwell's admission and condition only played a small role in why he was currently in a foul mood. He was angrily tying his tie while Maxwell watched him with a worried gaze. He knew he shouldn't be behaving this way, but it was hard for him.
He was doing his best to control his pheromones, his temper, and stopping himself from hauling Maxwell down and out in front of everyone until they found Michael. He was kicking himself for not bringing his phone since if he had, he could have prevented this.
He knew if he brought up why he wanted to use Maxwell's phone, he probably wouldn't get it, and with him unable to mask his emotions around Maxwell, there was no way he wasn't going to ask why Andrew needed his phone.
So, Andrew got dressed angrily, while Maxwell clearly felt like he was walking on eggshells.