Unwilling Vessel

• WOTC Official Reminder Textofficial rules
  Vigilance — Attacking doesn't cause this creature to tap.
• WOTC Official Reminder Textofficial rules
  Eerie — Triggered ability triggers whenever an enchantment enters the battlefield under your control and whenever you fully unlock a Room.

• WWizards of the Coast2024-09-20
  Official Ruling
  If a permanent with an eerie ability enters at the same time as one or more enchantments, its ability will trigger for each of those enchantments.
• WWizards of the Coast2024-09-20
  Official Ruling
  In the unusual case where Unwilling Vessel has +1/+1 counters on it and then receives an amount of -1/-1 counters that causes it to die, use the total number of counters that were on Unwilling Vessel when it died, including all of the +1/+1 and -1/-1 counters, to determine the value of X.
• WWizards of the Coast2024-09-20
  Official Ruling
  An ability that triggers "whenever you fully unlock a Room" triggers when a door becomes unlocked and the other door of that Room is already unlocked, or when both doors of that Room become unlocked simultaneously.

Rulings via Scryfall