Well Hodor is a short version of Hold the door so there is that.
Yes Bran did jump into young Hodor shortly and was able to control old Hodor through that too, the moment Bran got out of his mind he had that attack and became Hodor. Guess it was a combination of the weird timeline things with Bran leaving his mind at 2 different times at once and Hodor dying at that moment in the future. And he really wanted to hold that door and make sure he can help.
Was just all too much.
