The anomaly begins at about 2 minutes 42 seconds into the video. You can see the crew being bounced around. The separation of the four booster rockets from the first stage appears to be abnormal.
Below is a comparison of normal booster separation and what happened earlier today.
I made a comparison between a normal #soyuz booster separation and that of #SoyuzMS10 this morning. Differences are clear. Debris and a less symmetrical look to this mornings failure. cc: @NASASpaceflight pic.twitter.com/qlaugluslF
— Greg Dutra (@DutraWeather) October 11, 2018
After a few seconds it also looks to me like the core is tipped sideways, definitely not in line with the air flow pic.twitter.com/BRZhHPf5m8
— Amy Parent (Trackcident) (@amyinorbit) October 11, 2018