Way back when, when the pony tailed engineers were designing today's debacle to the Emperor's specifications, they called out a new way for spaceships to come together. The Low Impact Docking System, better known as LIDS, was going to be the modern day answer to mating. Any two spacecraft, regardless of type, would be able to connect, transfer information, power, fluids, and even crew if suitably equipped with a LIDS docking adapter.
The LIDS mechanism is covered by US patent 6354540, titled "Androgynous, Reconfigurable Closed Loop Feedback Controlled Low Impact Docking System With Load Sensing Electromagnetic Capture Ring."
The password is "androgynous," defined as "being both male and female." It can go "both ways." That is to say a vehicle with LIDS on board could dock with any other vehicle, including a copy of itself. So why is it, then, that a CEV as designed today, cannot rescue a crew from another CEV via a docked tunnel hatch?
Somewhere along the line, the Chief Engineer of the Universe's Apollo on Steroids fattened up. What do you have to do when you are overweight? Work some of the weight off, of course. And how has some of that weight been worked off of the CEV? We bet you already know the answer...yep, the LIDS now only goes one way.