running a quick pass of the numbers, the altitude at which you swap from accelerating upwards at a constant 0.5g relative to local gravity appears to be 4575 km, which takes 137 seconds to reach. After that, the ballistic throw to GEO is another 2 hrs 15 mins. You have to be grabbed at that point, or you begin to fall back...

Of course, this whole thing needs to be calculated properly as an orbital-tether interaction but in principle you can get through the radiation belts fast enough.

The big question is whether any materials are strong enough to take the dynamic loads involved in running a series of 10-tonne weights into buffers while accelerating a personnel module at 0.5g!

I'll leave further efinement of the model to the likes of SM who love meaningless detail...