I reviewed the slow mo of his "stumble" and not even a drunk person would stumble like that. His third step in getting up is to plant his left foot and drive himself to the right towards Allen. For one, a stumbling person wouldn't drive to the side like that. Then two, rather than try to get his right leg back on the ground to stop the stumble, he actually lifts it and keeps it elevated as he flies into Allen's knee. That's a clear dive.
*edit*
Also at the end his left foot also leaves the ground before his right even hits ground, even bracing his hand on the ground to maintain his trajectory before getting his legs back under him. If that's not a clear dive I don't know what is.