Jim keeps the phaser at the ready, and when the door slams open, he swiftly raises it to point directly at the person on the other side before he identifies her. He can't tell what the otter is doing or what she's facing, damn near blinded by the light shield it's emitting, but he's pretty sure this isn't the time to ask either.

He lunges forward at Hermione's shout, quickly sidestepping her to grab hold of the door with his free hand and slam it shut.