Nathan is a Sunbeam

Nathan is no longer in nursery.
His last week in nursery was a good one. He finally enjoyed going and referred to his teacher as his friend, Julia--wanting frequently to call her for a play date.
While happy at his recent contentment I began to worry about the transition into Primary.
His first week as a Sunbeam, I was subbing for the chorister. Nathan was clinging to my skirt until it sunk in that if he wanted a turn to help me he had to be sitting reverently on his chair like all of the other children I was choosing to help. At the end of the day I thought maybe there was nothing to worry about.
Week 2 in Sunbeams quickly reinforced all of my concerns. After chasing him around the room, catching him, and placing him upon his chair a dozen times, I found his dad. Ten minutes later Ray came back to report that Nathan had hid behind the pulpit but was sitting quietly and paying attention. Nathan's teacher had moved to sit close to him and so we felt all would be ok.
Next thing I know I've put Rilla to sleep and 3 people are hollering at me in urgent panicky voices for me to leave my class. Luckily, my friend took Rilla and I rushed out to learn that Nathan had taken off and evaded his teachers. I calmly searched the building and found him hiding under a small table. I asked him why he had run off and he answered, "I am scared of that big room!" I took him to his small classroom where he seemed excited to be. His male teacher inquired as to where his wife was. I realized she must still be searching for Nathan. I quickly fled searching for her. I found her shaking with terrifying sobs. She held me tight for what seemed like an eternity as she kept apologizing. I tried to soothe her while wanting the right words to come to mind to express my only concern for her well-being and my apologies for her having to be Nate's teacher, without sounding like an unfeeling parent who wasn't in the slightest worried about her son's safety....We'll see what happens this week. All I am praying for is that his teachers have experienced the maximum trauma possible and that any other Nathan behaviors will pale in comparison.