Vaedyn gets kidnapped during the groups short rest.  Likely by other drow since they were speaking undercommon.  The party chases after him at not full speed, they meet some watery creatures and promise to help them for elicit substances.  They continue their way through the mine killing a powerful demon before making their way into a tunnel that leads to a drider layer.  They know they must be getting close to where Vaedyn is being kept, so they take a much deserved short rest to heal up before the final grind of reaching him.