I'm not convinced that the rocuronium molecule can be "drawn" only from that side of the sugammadex molecule (which is the substituted lower rim side, not the cavity side, but never mind, that’s pretty large γ-cyclodextrin) (but also I'm not cyclodextrin supramolecular chemistry expert).
There are some multi-level computer simulations done in China recently. They have done some molecular dynamics, but they don't provide their trajectory data. Anyway, that trajectory is only several Å, from some pre-docked position to the optimized docked position.
There's a nice older study, not mentioned in your reference, working with sugammadex-like compound with bulkier substituents (carboxyphenylthio instead of carboxyethylthio), and besides hypothesizing on closed and open conformations because of π-π interactions of the aromatics, they show (or remind) that rocuronium can have different conformations where the morpholine residue (at right at your graphics, opposite to the quaternary ammonium) can be either in-plane, or perpendicular to the plane, so that it can nicely accommodate, or somewhat lock-in once it enters the cavity (besides other interactions), but they seem to also assume that it's the (only) entering side, which I'm not convinced of.
Encapsulation is rather statistical dynamics process with thermodynamic equilibrium, than a sucking in.
They also have a nice X-ray structure data of the encapsulation complex, but again, that's not sugammadex, exactly. Its X-ray crystal structure is in the Angew. Chem. article, the substrate is in the same orientation, but I think it's not because it can enter from one side only with the signle orientation only, but rather because of the electrostatic stabilization.
- Li, L.; Zhou, Y.; Wang, Z.; Wu, C.; Li, Z.; Sun, C.; Sun, T. Theoretical Studies on the Mechanism of Sugammadex for the Reversal of Aminosteroid-Induced Neuromuscular Blockade. Journal of Molecular Liquids 2018, 265, 450–456.
- Cooper, A.; Nutley, M.; MacLean, E. J.; Cameron, K.; Fielding, L.; Mestres, J.; Palin, R. Mutual Induced Fit in Cyclodextrin–Rocuronium Complexes. Org. Biomol. Chem. 2005, 3 (10), 1863–1871.
- Crystallography Open Database – Information card for entry 7150103
- Bom, A.; Bradley, M.; Cameron, K.; Clark, J. K.; Egmond, J. van; Feilden, H.; MacLean, E. J.; Muir, A. W.; Palin, R.; Rees, D. C.; et al. A Novel Concept of Reversing Neuromuscular Block: Chemical Encapsulation of Rocuronium Bromide by a Cyclodextrin-Based Synthetic Host. Angewandte Chemie International Edition 2002, 41 (2), 265–270