At the risk of sounding like a broken record, Loki will want to just kill her.

And actually, he could use an illusion to disguise himself as her, and he mimics voices very well. He just wouldn't be able to do anything else magical since that'd pretty much blow his load as far as diminished powers go.

Blowing the door wouldn't effectively free up anyone, since then there'd be a massive fight. Subterfuge is going to win the day on this one.