i don't think you have to worry about dogs looking to you for protection, there are plenty of stories of dogs fighting for their owners. my family's got a wuss who will curl up with you during a storm but any time a stranger comes around he's front and center. the question is, though, do you care about your buddy too much to let him get mauled? better or worse i don't think i could leave a dog behind, i'd just try to open it up enough to empty my guns.
i think if you have the ability, another person around is your best bet, if you're genuinely worried about getting ambushed while you're dressing. the key though is situational awareness, just like any time you're carrying a gun. you have to have your antenna up and be ready to change posture in a heartbeat.