Is there a way to get into display cases in the diamond store without triggering the alarm?

Our crew had a good start at stealthing the mission, taking out all the guards and controlling the civilians. However, when we broke the first display case, all our effort was for naught since it triggered the alarm and our escape vehicle took off.

Is there a way to disable the display case alarms?

You can disable the display case alarms in the diamond store heist by using the keycard that you can find on the store manager on the display case alarm panel;

The location of the keypad is random, so far I've seen it spawn in the security room, by the stairs, and in the offices upstairs.