The Shaman will almost definitely wind up getting destroyed.
It's a missed trigger, which the Shaman player controls (since Tabernacle grants the trigger to the creature). Once it's missed, the Tabernacle player should call a judge for a ruling. The correct ruling is that the Tabernacle player will have the option of letting the trigger resolve later, and since the trigger has a default action associated with it ("...destroy this creature
unless you pay
"), the ability will immediately resolve to the effect of destroying the Shaman.
edit for relevant quote from the infraction procedure guide:
Definition
A triggered ability triggers, but the player controlling the ability doesn’t demonstrate awareness of the trigger’s existence and/or forgets to announce its effect. If a triggered ability has been partially or incorrectly resolved, instead treat it as a Game Play Error — Game Rule Violation.
A trigger is considered missed once the controller of the trigger has taken an action after the point at which a trigger should have resolved or, in the case of a trigger controlled by the non-active player, after that player has taken an action that indicates they have actively passed priority. Players may not cause triggered abilities to be missed by taking game actions or otherwise prematurely advancing the game. For example, if a player draws a card during his or her draw step without allowing the controller of a triggered ability that would trigger during that turn’s upkeep to resolve it, place that trigger on the stack at this point and issue no penalty.
Examples
A. A player controls Braids, Cabal Minion. After he has declared attackers, he realizes that he has failed to sacrifice a permanent at the beginning of his upkeep.
B. A player realizes that she forgot to remove the final counter from a suspended spell.
C. A player forgets to pay the cumulative upkeep cost for a creature.
D. A player controls Soul Warden and forgets to gain 1 life when a creature enters the battlefield under his opponent’s control.
Philosophy
Triggered abilities are common and invisible, so players should not be harshly penalized when forgetting about one. Players are expected to remember their own triggers; intentionally ignoring one is considered Cheating — Fraud. However, remembering triggers that benefit you is a skill. Therefore, players are not required to point out missed triggers that they do not control, though they may do so if they wish.
The controller of the missed trigger only receives a Warning if the triggered ability is generally considered detrimental for the controlling player. The current game state is not a factor in determining this. Whether a Warning is issued or not does not affect how the trigger is handled, and Failure to Maintain Game State penalties are never issued to players who did not control the ability.
Judges should not intervene in a missed trigger situation unless they intend to issue a Warning or have reason to suspect that the controller is intentionally missing his or her triggers.
Additional Remedy
If the trigger specifies a default action associated with a choice made by the controller of the trigger (usually "If you don't ..." or "... unless"), resolve the default action immediately without using the stack. If there are unresolved spells or abilities that are no longer legal as a result of this action, rewind the game to remove all such spells or abilities. Resulting triggers generated by the action still trigger and resolve as normal.
If the duration of the effect generated by the trigger has already expired, or the trigger was missed more than a turn ago, instruct the players to continue playing.
Otherwise, the opponent may choose to have the controller play the triggered ability. If they do, insert the forgotten ability at the appropriate place or on the bottom of the stack. No player may make choices involving objects that were not in the zone or zones referenced by the trigger when the ability should have triggered. For example, if the ability instructs a player to sacrifice a creature, that player can't sacrifice a creature that wasn't on the battlefield when the ability should have triggered.
