To get Shadowheart out of the pod in Baldur's Gate 3, follow these steps:

• Examine the console to the right of Shadowheart's pod. You will see a socket where an item can be placed.
• Go through the door to the east of Shadowheart's room.
• In that room, walk past another pod to the back where you will find a dead thrall. Search the body to find an Eldritch Rune.
• Return to Shadowheart's room and use the Eldritch Rune on the console socket.
• Place your hand on the console when prompted.
• When the new prompt appears, select the option related to Illithid (Wisdom) to will the pod to open.

Shadowheart will then be freed from the pod and join your party for the rest of the Nautiloid tutorial area

. Additional notes:

• Some classes with Arcana proficiency or specific skills may attempt to hack the console without the rune, but the rune method is the standard way.
• There is also a chest near Shadowheart's pod that can be opened with a key found in the eastern room for extra loot.
• If you choose not to free her at this point, Shadowheart will survive the Nautiloid crash and can be met later in the game, though she may be less friendly initially

This method is straightforward and allows you to add a powerful cleric companion early in the game.