For me the real interest is not to finish or not a mission. it is to find bugs to help programmers and to have the best possible game. In fact I'm more tester than player. But to continue such a development, it is necessary to enjoy players and to give them an "unbugged" program.
Had you seen that climbing staircases is possible, at least in entrance, when base is under attack and not during "outside" missions ?
The real purpose of my message was to say that the problem was not solved in 22070.
I don't know on what problem programmers worked between 21848 and 22070 but if they worked on this, I think it was good to say result of tests.