The distinction is often slight, of course.οἱ σὺν ἀσπίσι πολέμιοι ἀπόλλυνται.
The enemies who have shields are being destroyed.
οἱ πολέμιοι σὺν ἀσπίσι ἀπόλλυνται.
The enemies are being destroyed (along) with their shields.
The placement of ἐν τῷ Σιλωὰμ seems a bit odd to me. I would expect eitherLuke 13:4 ἢ ἐκεῖνοι οἱ δεκαοκτὼ ἐφ' οὓς ἔπεσεν ὁ πύργος ἐν τῷ Σιλωὰμ καὶ ἀπέκτεινεν αὐτούς, δοκεῖτε ὅτι αὐτοὶ ὀφειλέται ἐγένοντο παρὰ πάντας τοὺς ἀνθρώπους τοὺς κατοικοῦντας Ἰερουσαλήμ;
ἐκεῖνοι οἱ ἐν τῷ Σιλωὰμ δεκαοκτὼ ἐφ' οὓς ἔπεσεν ὁ πύργος, where the emphasis is which men (the ones in Siloam) or
ἐκεῖνοι οἱ δεκαοκτὼ ἐφ' οὓς ἔπεσεν ὁ ἐν τῷ Σιλωὰμ πύργος
where the emphasis is on which tower (the one in Siloam.)
But what is being emphasized here? The location not of the men or the tower itself but of the falling? Can there be a distinction between the location of the tower and the location of the disaster? What is the difference, for that matter, in English, between
When the towers in New York fell, the world changed.
When the towers fell in New York, the world changed.
Ask 100 fluent English speakers what the difference is. Most will say there is no real difference, and the rest will not be able to agree on what the difference is, because it is so slight. Most will say the difference is more stylistic, and may say one just sounds a little better than the other.
Getting back to Luke, every translation I have seen, for example,
KJV: Or those eighteen, upon whom the tower in Soloam fell...
blurs the distinction (rightly, I think) by using the phrase "the tower in Siloam" except for this one:
which contradicts the usual Greek rule, and this oneTCNT: Or those eighteen men at Siloam on whom the tower fell...
which follows more closely the Greek order, but seems somehow like strained English.Rheims: Or those eighteen men upon whom the tower fell in Siloe...
My feeling is that the word order here, as so often happens in Ancient Greek, is more euphonic than semantic.