I added to the et_headshot script the random set up to mimic the way the original map controls might be operated at the start of the match by Humans. Two obvious (to me) ways that these might be changed during the match would be (1) a fake toi floor trigger as an event say when a team member gets to the opposite teams doors and (2) after a self-repeating delay using recursive triggering.
If you would like to have a go as a learning experience here are some helpful references;
Scripting Reference by chruker (a quick bible to map scripting)
FritzBot_Buttons_And_Levers the wiki topic by CrapShoot that uses floor triggers. This topic shows a specific example from Adlernest using floor triggers. For your case a bit less is needed (just most of the first half of the topic). The helper ents communicating with the aiscript are not likely needed nor the aiscript changes at the end of the topic. (There are already roam actions at the far ends for health and ammo) The globalaccums (5, 7) used as lockouts in the script might be used differently to lockout changes from re-occurring too soon, allowing at a minimum, time for the changes to take effect.
Other topics that might help are;
Fritzbot_Map_Scripting and
Debugging_Script_files. And use /viewpos in the console to determine your position to find coordinates for the origin and calculate values for the mins and maxs extents for the floor triggers.
It is a bit of a stretch as a first go at script file changes but if you make the attempt you may find that you can handle the task and have much fun at the challenge.