Basically during a 4 man Gorod EE boss fight I went down, and my friend revived me during the cuts cent between he dragon and Nikolai fights, after being revived I could not switch weapons, could not jump, couldn't pull out ny shield, etc. The only thing it let me do was use the mark 3's. After finishing the fight I realized that zombies had stopped aggroing, after boxing, buying a wall weapons, etc to try and fix not switching weapons I eventually tried pack a punching which basically made me able to switch weapons and use my shield, etc. The only thing I couldn't do was jump and hear, as the game sound was permanently muffled like when you are down, I could be damaged by traps and splash damage but nothing would aggro me. Here's a very bad clip i took before we all got off after messing around for a round or two