I would assume that an exit door swings out and not in. I would also think that it would be a steel door in a steel frame. I don't see how someone could kick that in.
Code states that the egress doors must swing in the direction of egress and you are correct in assuming that it would be a steel door - no way he was able to "kick it in". Some had to have let him in...
"Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure or nothing at all." - Alex Lowe