It doesn’t happen like you think in the movies.
For the first part, everyone is awake. They’ve been awake for about 15 minutes. That’s because the Firewatch (recruits who rotate every hour during the night to watch out for — nothing, nothing really happens, but it is part of the training) are told at least 15 minutes before “lights” that the day is about to start.
When the first of them is told “15 minutes to lights”, they will cry out “15 MINUTES TO LIGHTS!” which will be echoed throughout the barracks. That’s your real wake-up call.
From there, you’re awake, and just laying there gathering yourself, steeling yourself for the day to come.
The Firewatch will cry out “10 MINUTES LIGHTS!” and then “5 MINUTES TO LIGHTS!”
Finally, the lights flick on and the Drill Instructor is screaming “LIGHTS! LIGHTS! LIGHTS!”
Within about 12 seconds, an entire platoon of 80 recruits look exactly like this, online, ready to go.
By ready to go I mean that in the next 5 minutes, they will be completely dressed, have their gear drawn, beds made, and probably be outside and in formation ready to march off to get breakfast.
That’s what I think really makes things so strange. There isn’t a lot of dread like this question seems to expect. There is just acceptance. You’re told by your recruiters and other DIs that this will happen. You’re told what to do when it happens. You know it’s happening as it happens. It’s no surprise. It’s not fun, but at least everything you need to know is told to you, by the numbers.
So there isn’t a lot of dread or fear in that first moment.
Just a very sincerely feeling of, “Oh Lord, please don’t let me screw up doing all the things this scary man says to do so that he doesn’t notice me on the first day.”