As far as how she got in.....
Do a search for hotel room safes. You don't even need quotes around it. See what shows up on the first page.
That being said - I have used the safe in the hotel room for my electronics and some jewelry (expensive by my standards, but not THAT expensive). I know the risks. I usually only do it if I know I'm going to be out a short time, and usually only when there is no maid service.
And usually only if my only alternative is to lug all the stuff around with me, and it would likely be less safe to have it on me than in the room safe.
Nothing is ever secure in a hotel - not even locked in the safe. There's a reason hotels say they are not responsible for anything left in the room or stored in the hotel safe.