This isn't the first time the delivery of the dialogue in this scene has been bashed. Personally, I think if the guy on the intercom had been emotional it would have come across as too melodramatic or even campy, especially since it's only a voice and you never see an actor's face. As it played out, it kind of makes sense. People, when faced with traumatic situations like that, often emotionally shut down for self-protection. They don't always fall apart and start balling in grief.