doesn't say if the person lives on the premises or not...

'only 1 person having the key of the main door,all exit are closed with metal grills,'

If its locked from the inside, I would think they must...

This is taken from my days back in SA where security gates and bars on the windows are on every single house you go to and yes, they will be locked from the inside unless its a keylock on the actual gate and not a padlock... Those padlocks are a pain to unlock from the outside, trying to hold and manouver them...and if you look at the one on that gate, its got a solid metal slab across that portion of the lock.... so it will be really difficult to open from the outside and you cannot see what you are doing...