This is a terrible method. What if a unit enters while another one is in there? Once one leaves, it screws it up.
Dungeon
Events
A unit enters Region (Over the dungeon)
Conditions
Unit type equal to YOURUNIT/PLAYER
Actions
Turn on Dungeon Nigth
Dungeon Nigth
Events
Every 0.1 seconds of the day
Conditions
Actions
Set Day Time 24:00
Dungeon Off
Events
A unit leaves YourRegion
Conditions
Unit Type Equal to URUNIT/PLAYER
Actions
Turn off Dungeon Nigths
This is the only thing I can think of.
Custom script: if ( GetLocalPlayer() == Player(NUMBER OF THE TRIGGERING PLAYER) ) then
Game - Set the time of day to 24.00
Custom script: endif
if GetLocalPlayer() == Player(0) then
call SetDayNightModels("something","something")
endif