I disagree about a prohibition on entering the Sanctuary.
From the 2002 General Introduction to the Roman Missal (GIRM) which can be accessed from
romanrite.com/girm.html :
“162. The priest may be assisted in the distribution of Communion by other priests who happen to be present. If such priests are not present and there is a very large number of communicants, the priest may call upon extraordinary ministers to assist him, e.g., duly instituted acolytes or even other faithful who have been deputed for this purpose. In case of necessity, the priest may depute suitable faithful for this single occasion. These ministers should not approach the altar before the priest has received Communion, and they are always to receive from the hands of the priest celebrant the vessel containing either species of the Most Holy Eucharist for distribution to the faithful.”
Clearly the instituted acolyte is going to be in the sanctuary. He will have been in the entrance procession, probably carrying the cross, and he will have been sitting in the sanctuary throughout Mass. So it is not a prohibition on being in the sanctuary.
Rather the instruction is “These ministers should not approach the altar before the priest has received Communion …”. So the point is that the priest receives Communion first. The lay ministers should not go to receive Communion until the priest has finished receiving Communion.
Remember that the justification for using Extraordinary Ministers is to avoid a situation where “the Mass or other service may be unreasonably protracted.” (Holy Communion and the Worship of the Eucharist Outside of Mass, published by E.J. Dwyer, Sydney, 1975, ISBN 0-85574-401-4, page 9, n. 17).
Say an Extraordinary Minister is sitting in the back row. It will take 50 seconds to walk from there to the altar. How is it helpful to require them to remain at their seat until after the priest has drunk the Blood of Christ. It wastes time, when the intention of using them is to save time.
So my understanding is that the intention of 2002 GIRM n. 162 is not to stop them entering the sanctuary or approaching it. Rather it is to make sure that the priest receives Communion first.