Mary hurt all over and she knew she'd need a whole lot more than a shower, but having Johnny here meant that she would be safe soon. She couldn't help but joke around just a bit as he freed her hands. She laughed softly and had her mouth open to fire off a snarky reply to the comment about the shower when she heard the gunshot. She hadn't even heard anyone enter the room, but someone apparently had.
Gunshots weren't as startling for Mary as they might be for some. It could just as easily be 'friendly' fire, given that she'd grown up in a guntoting family and she half-expected the rest of them to burst through that door any minute.
As such, it took a moment before the panic started to set in and she looked at Johnny to see if he'd been hit. She hadn't been shot, but that didn't mean that they were safe. As much as she wanted it to.