When the missiles launched from the Shadow Mercenaries base, Alex and the others headed out of the base to see what will happen next. Though there wasn't much information at hand regarding the missiles, Evangeline who took a look at the plans knew it was some kind of biological weapon, and they were set to strike certain keypoints. Based on what Hektor kept on screaming, the missiles should have devastating effects that could affect the whole world, Alex and the others just didn't know what kind of effect it had. All they knew was that it was entirely possible watching what the missiles did would be the last thing they saw.
At least if they and the world were going out, they wanted to be able to witness how everything would end.