Rulings
Q1: Does this card's When Attacking effect prevent deletion in battles against Security Digimon?
Yes, it is not deleted.
Q2: Does this card's When Attacking effect prevent deletion even when my opponent's deleted Digimon has Retaliation?
No. Deletion by Retaliation is deletion by an effect, not deletion in battle.
Q3: If I have 7 cards in my hand upon an attack by my Digimon with 2 of this card in its digivolution cards, can I draw a total of 2 cards from both instances of this card's effect?
No, you can't. Upon the attack declaration, the inherited effects on the 2 copies of this card simultaneously trigger, then the player determines the activation order. However, because your hand increases to 8 cards from Draw 1 on the 1st card, the effect's conditions aren't met for the 2nd card, so the effect doesn't activate. As a result, you only draw 1 card.
Data Sources
Lv.4 TeslaJellymon LM-003 U Champion | Data | Mollusk [When Attacking] By trashing 1 blue card in your hand, this Digimon can't be deleted in battle for the turn. --- Inherited: [When Attacking] If you have 7 or fewer cards in your hand, <Draw 1>.
Lv.4 TeslaJellymon LM-003 U Champion | Data | Mollusk [When Attacking] By trashing 1 blue card in your hand, this Digimon can't be deleted in battle for the turn. --- Inherited: [When Attacking] If you have 7 or fewer cards in your hand, <Draw 1>.
Lv.4 TeslaJellymon LM-003 U
Champion | Data | Mollusk
[When Attacking] By trashing 1 {{Colour|blue}} card in your hand, this Digimon can't be deleted in battle for the turn.
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Inherited: [When Attacking] If you have 7 or fewer cards in your hand, <Draw 1>.Lv.4 テスラジェリーモン LM-003 U 成熟期 | データ種 | 軟体型 【アタック時】自分の手札から、青のカード1枚を破棄することで、ターン終了まで、このデジモンはバトルで消滅しない。 --- Inherited: 【アタック時】自分の手札が7枚以下なら、≪1ドロー≫。