Hi, NonCatholic,
Let me try my hand at this and see if these responses address the topic:
The mental picture I had when you asked this question was why didn’t one or more of the Apostles drop to their knees and begin to chew on Christ’s hands and feet?
As my imagination continues… so, here I see the Apostles going up to Peter and asking him what is going on. Peter may have responded, “I don’t know about that - but, there is one thing that I do know: Christ has the words of eternal life!” This second part (John 6:68) was said under the inspiration of the Holy Spirit… but, no one understood what Christ was talking about until He revealed what He meant at the Last Supper (Mark 14:22).
Christ consecrates the common bread and tells the Apostles “This is my Body”. Christ in now, physically, holding Himself in His Own Hands - and gives it to the Apostles to eat (as in gnaw on). There is no natural explanation for this. All we have are the statements from Christ (and, by the way, that is all you have, too!

) Christ told His friends to “do this” as in repeat this process (consecrating common bread and wine into the Body, Blood, Soul and Divinity of Christ). The Apostles were now directly given the power and authority - by God Himself - to, in fact, “do this”. And this would be the very beginning of the priesthood in the CC.
As I understand Heb 10:11- “Every priest stands daily at his ministry, offering frequently those same sacrifices that can never take away sins. But this one offered one sacrifice for sins, and took his seat forever at the right hand of God; now he waits until his enemies are made his footstool. For by one offering he has made perfect forever those who are being consecrated.”
Christ died once for all. The Catholic Priest at Mass in not ‘re-killing’ or ‘re-sacrificing’ Christ. Rather, the priest is following Christ’s directives to, “…do this in memory of Me…”. The Priest, in the person of Christ, is consecrating the common bread and wine into the Body, Blood, Soul and Divinity of Christ - the Son of God.
Christ gave Peter the Keys to the Kingdom (Matt 16:19). Peter (and by extension, his successors the Popes - all the way to Benedict XVI) has the power and authority and responsibility to make what changes are necessary. The CC has determined that a tabernacle and an altar will be an essential part of a Catholic Chruch so that the un-bloodly sacrifice of the Mass can be celebrated.
Ultimtely, it really rests on faith.
Either one believes what Christ said - as plainly recorded in your own Bible - or, one believes something and/or someone else. What else is there?