I'm not sure if the "Until end of turn" duration of Invulnerability last long enough or if Loki's effect triggers before then.
"Invulnerability - Basic Action Card 30 of 132
Your attacking characters that are knocked out (this turn) return to the field)
Global: Pay (1 Blast). One target character gets +1A (until the end of the turn)"
"Loki - Illusionist 80-132
When fielded, take control of an opposing character. At the end of the turn, knock out that character (place it in your opponents prep area); it deals damage equal to its attack to your opponent."