I could only see a shadow of the man from the lower right corner. What I could clearly see, was the priest in his green vestments remarkably maintaining his composure throughout the entire 1 minute event.
Fortunately, the priest was not alone. There were people available to grapple with the intruder and keep him away from the altar, if that was his goal.
There was an Altar Girl seen on the right side of the Altar.
A school girl who was clearly terrified.
Our Lady of the Angels does not have altar girls - that girl/lady is in the choir which is located behind the altar in that church.