What exactly is a sync?

The group is in a hallway deep in a corp headquarters basement. They encounter a secured steel door with fingerprint panel on the wall next to it. Sigmond attempts an Interface sync to force it open.

Here’s what it looks like at the game table, in real life:

The panel has a Cyber score of 4.  Sigmond has a Cyber score of 5 and one rank in Ace Hack, plus he’s high on a dose of Silica, giving him a total of 8 dice. However, the device is hardened, limiting Sigmond to a maximum of four dice.

Sigmond’s player Slings [4] to attempt the hack and the Admin Slings [4] for the device. They both produce no sixes, so they each remove a die and go again.  Both Sling [3].  Sigmond manages a six. The Admin sees a miracle roll and produces three sixes!  Both are successful, so each removes a die and goes again. Both Sling [2]. Sigmond gets a six, and the Admin does not. The hack is successful.

Here’s what it looks like in-game (in the fiction):

Sigmond looks at it. His pupils dilate and contract rapidly, then the panel flashes green and the door whooshes open. The whole thing takes approximately three seconds. Sigmond snaps back into focus; everyone notices a flash of worry in his eyes that quickly dissolves.

Here’s what’s happening under the curtain, in Sigmond’s head; Sigmond’s player and/or the Admin might decide to narrate something like this aloud as the dice Contest is happening, though it’s strictly for flavor and not at all necessary:

Sigmond mentally scans the device with nothing more than a thought; his neuralnet wirelessly handshakes with the device. A portion of his vision becomes occupied with a schematic of it, and he pipes over a few threads of code. One of the bulkheads he thought was vulnerable had some hidden ICE and reflects his script. He cobbles another subroutine and probes a different part of the logic; again, it is surprisingly resilient and error trapping subsumes his work. A third time, nearing desperation, he writes a patch and lays it across two datapaths in the schematic to short them. It works. The whole 3D drawing turns green in his mind’s eye, and he has total control over it.

In any case:

Sigmond operates the device within the bounds of its normal operation; he decides to have it unlock.