Imagine that a senior Conservative politician had ducked out of a House of Commons vote, claiming to be sick. Imagine that Guido Fawkes and others had video of her in action not long before the vote. How much attention would the BBC have paid to this? How much deep investigation of this Conservative politician would Today, Newsnight etc have conducted?
Now see what happens when probably the third most senior Labour Party politician, Diane Abbott does just that?
Here's about the only BBC report that I can find http://www.bbc.com/news/uk-politics-38840352
Pathetic but why should one expect better of the media wing of the Labour Party?