Confused after 1st attack - spoiler

The holes were too deep they said they tried to flood them with salt water but they were just too deep meaning I don't think they could have got explosives down there but I didn't understand why they didn't seal off the exits and entrances to the holes but that probably wouldn't have helped when millions are piling at the door it'll finally break

a lot of thing didn't make sense. After the first attack. One would have thought that the whole world would have safe shelters to hide from these creatures on Apocalypse day and not wait on the park to see if the creatures would appear or not.