Rodolphus made himself a glass of water, he just didn't have a taste for anything else. After taking a drink he held the cup out to Rabastan in case he wanted a drink as well. "Well there were witnesses there. Let's see - Evans, Potter, Snape, Bellatrix, Sirius, myself. Narcissa and Avery were there too but I don't think they followed after I chased Evans down."
It really would be a shame if he was sent to Azkaban over something that had been such a colossal screw up on his part. What he'd been able to do to impress Bellatrix until that point, mainly murdering that Muggle family, had all been lost when he hadn't been able to drag Evans back and dump her at Bellatrix's feet.