The goalkeeper's England spot for this summer's tournament in Russian Federation has been in jeopardy since he lost his place at West Ham in December following some inconsistent performances.
Joint-owners David Gold and David Sullivan, whose decision to uproot the club from its old Upton Park ground to the former Olympic Stadium is behind the anger, are understood to have left their seats for their own safety.
The unrest had been simmering in recent weeks. "But for the time I've been here, I've certainly enjoyed it".
But this was not just a case of those tensions spilling over.
Icelandic winger Gudmundsson has been one of the stand-out Burnley players this season, scoring twice and setting up six goals as well as many more chances with his excellent delivery from the left. In playing a team who have failed to score in 5 of their previous 7 away games, this could be the flawless opportunity for the Hammers to do just that.
Burnley were once as high as fourth and can close to within two points of Arsenal in sixth with victory over West Ham on Saturday before the Gunners meet Watford on Sunday.
A third successive Premier League defeat saw West Ham slip closer to the relegation zone and Moyes accepts his side are going through a hard spell. Coupled with the fact that they play Barcelona in the week and I think they are worth opposing at [1.33].
Moyes added: "I think as a supporter you can't cross the line, as a supporter".
The atmosphere in East London turned when the visitors took a 1-0 lead through Ashley Barnes during the second half. I think you've also got to say that the players want to get on with the game, they want to play. "It's tough for them at the moment but they need to stick with the players", he said. Here are four things we learned from today's game. "Footballers are all winners - we want to win every game so even with 40 points we are not going to put the handbrake on and stop showing up at the weekend".
The stats are in our favour, both teams should be relatively confident given some good results of late, and the fact that the match has so much riding on it might just mean that we see two teams going for a win rather than trying to avoid defeat.