Poland's Katarzyna Niewiadoma finished second to take the leader's yellow jersey from defending champion Vollering who dropped to ninth overall.
A pile-up with six kilometres to go involving 10 riders including Vollering decimated the peloton in the run to Amneville in northeastern France.
The Team SD Worx leader now trails 1min 19sec behind her main rival Niewiadoma who had started the stage 34 seconds behind Vollering.
Shocked, suffering back pain and cuts to her left thigh, the Dutch star took more than a minute to remount to finish the stage with courage.
The fall split the peloton and in a four-way sprint, Vas dominated Niewiadoma, German Liane Lippert and American Olympic champion Kristen Faulkner.
On Friday, the sixth stage covers 159km with a climb up the the Côte des Fins less than 15km from the line which could prove decisive.
The Tour finishes on Sunday with one of cycling's most challenging climbs up Alpe d'Huez.
