Watch it again - we're being hit on the break. Him and Rojo are the last two defenders and the Newcastle player is sprinting towards Rojo. If Andreas steps up and the defender sprints past Rojo then he has a one on one opportunity. Instead Andreas is a bit deeper so if yer man takes on Rojo, he can then get across to make an interception. If they're both in line then you're making his life easier as he just needs to get past Rojo to be in.
Also the Newcastle lad on the left is in acres of space and can look across the line, if Andreas is in line with Rojo, he could easily just make sure he's in line with the the both of them too... So trying to play offside there would be totally pointless.
What do you mean running past his defensive line? Him and Rojo are literally our last two defenders there! He has to work back because we were short of numbers at the back with being caught on the break.
See above, he hasn't drifted anywhere, he's literally getting back to help out because all our defenders/CM's are caught up field as we're being hit on the break.
And it's Maguire who is in the best position to close down the shot, not Andreas.