How does the body appear in two places simultaneously? I don't believe you can find in Scripture the physical body of Jesus in two places at once.
Doesn't that assume one answer to the question under debate? If the Emmaus meal is the Eucharist, then that's your Scriptural evidence, and that's the place in Scripture where you find the ... body of Jesus in two places at once. To say you can't find it in Scripture is to say you can't find it here, but that was what was being debated, wasn't it?
I do think it's important to those who want to know what the RC's teach about sacramental presence to understand that "real" and "substantial" do not necessarily mean what we NOW mean by those words.
I elided over "physical" because that's an unclear word. Literally it means "growthy", and I guess you mean something like "natural". But do we want to say the resurrection body is a natural body or that it grows? It certainly does not seem to obey the laws of physics or of biology. "Substance" also has changed in meaning (which will affect conversations about transubstantiation), while "real" ("of a thing", "pertaining to a thing", "like a thing", 'thing-y' or 'thingish') has never been a very precise word as far as I can tell. What is a "thing" anyway?
"appear in two places" is a bit of a stretch; the Gospel does not exactly say that. It says that they did not recognize Jesus till the bread was broken. One can read verse 31 in the sense that they saw Jesus in person but only after the bread was broken, or that they only saw him in some miraculous sense in the bread. Either way, the incident describes a miracle and links Jesus's presence with the bread. The pedestrian reading that Blue Duncan prefers, -- that there was no miracle at all, but rather a recognition of a personally heretofore unfamiliar "brother" is, however, going way outside of what is in the scripture, and is contradicted by v 16, which indicates the supernatural origin of the unrecognition.
Incidentally, the Eucharistic presence of Christ is indeed not bound by time and space to one mass at a time.
their eyes were held, that they should not know him (Luke 24:16)he took bread, and blessed, and brake, and gave to them. And their eyes were opened, and they knew him: and he vanished out of their sight (vv 30-31)
they knew him in the breaking of the bread. (v 35)