Jut after 14 minutes 20 seconds astronaut Michael Fincke had to interrupt his EVA due to a loss of pression in his main oxigen bottle.

The anomaly was promptly detected by Russian Flight controllers who ordered both Fincke and Padalka to immediately reented the station.

Full story at space.com

A spacewalk intended to replace a faulty circuit breaker on the exterior of the International Space Station was cut short when the primary oxygen bottle on Astronaut Mike Fincke's Russian space suit began losing pressure faster than expected.
The overall pressure in Fincke's suit remained stable at all times and he was not in danger. A backup oxygen tank available on his suit was not needed.