[Thankfully there's nobody in the dome who might confuse costume for reality, because Rebecca's taken to dressing up like it's nobody's business. Halloween was always her favorite holiday, so any excuse to dress up-- bar masquerades counting, means a fun time to be had by her. So she goes full out, though she might be hard to recognize at first in the chosen costume. Acting the part, at least until it gets old.
And the mask, while amazing at first, will slowly unwind as the night goes on because it's ridiculously uncomfortable and it's a party, drinks need to be had.]