On the night of Mr. Melvyn's murder, Drag was dancing at the Boom Boom Bar wondering whether she should tell Detective Nielsen that she'd probably given him gonorrhea the last time they had sex.    In the end she decided against it, figuring that the bastard deserved all he got.     She did decide, thought, that she'd better tell Red about it - they'd just started seeing each other, and she didn't want him to figure it out the hard way.