This is the way I did it:
Disarm and unlock the safe with the statue.
Get an invisbility potion ready in your quick slots
Loot the safe, but don't take the statue until you pause the game.
While still paused, and with the statue in your inventory, drink the invis potion.
It may take a few tries to get the timing right, but I have done it several times this way without triggering the alarm.
Walk in darkness friend!
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"This place will be your tomb."