Keep breathing and note that this position also narrows your field of sight. You will find that moving and turning serves you well to create a better field of sight and learn to do so even if the arms are free. practice this.
Work in teams of three or more with all of you cupping your hands over the back of your necks. Two or more work using their bodies and legs to fell the one and he has to stay upright and mobile. This is good to teach you to work with the body even if the arms are in a bad position or if you suffer from shock and cover your face and ears and if you tense up against the others you will fall or get hit and learn from their tension to relax and keep moving and to avoid fighting for land. This is sometimes a must in bodyguard work but the approach is different. Work and change jobs from time to time and you will learn to move better and to stay relaxed under tension.