Help with a script.

[Khyrpa]

AddEntityCollideCallback("Player" , "*nameofyourarea*" , "flashspawnsomething" , true , 1);
that into OnStart

then do smthing like this

void flashspawnsomething(string &in asParent, string &in asChild, int alState)
{StartEffectFlash(1.0f, 1.0f, 1.0f);
AddTimer("blehblabh", 1.0f, "timedteleport");
}
void timedteleport(string &in asTimer)
{TeleportPlayer(string& asStartPosName);
}

that will actually do everything in just 1second, but with tweaking the start effect flash functions numbers and the timer, you can slow it down...
Or do you mean whole another level/map? if so then use:
ChangeMap(string& asMapName, string& asStartPos, string& asStartSound, string& asEndSound);
instead of teleport