Hi Nicolas, this is an example, the 4 principles of the theory that you have asked me before, you can find the them (吞Swallow, 吐Spit, 浮Float, 沉Sink) in this part of demonstration.
That's a great two man hand set. We will work some of it into our own training. Thank you for sharing so generously on RU-vid. Keep the traditional arts alive and well, and keep practice. All the best! Laoshr #60 Ching Yi Kung Fu Association
The word 排 which is not meant ribs(排骨、肋骨),is conveyed the powerful offensive of opponent as an idiom in Chinese 排山倒海之勢(strong enough to topple the mountain and overturn the seas), therefore this movement is how to break off the powerful offensive from your opponent.