ambiguity & irony in Sophocles' Electra

This is the part of the final exchange between Electra and Aegisthus. It illustrates how the hearer's assumptions control his understanding of an utterance. Sophocles brings Aegisthus back to the royal house ignorant of what is going on inside. Aegisthus has been told that two unidentified foreigners  arrived with news of Orestes' death in a chariot accident. He is elated at the news and arrives at the house bursting with optimism about his future. The avenger of Agamemnon's murder is dead, so he assumes. Electra, who intends to deceive, plays on the ambiguity of certain expressions which Aegisthus in his current frame of mind is bound to misunderstand.

Sophocles Electra 1442-1449
{ΑΙΓΙΣΘΟΣ}
Τίς οἶδεν ὑμῶν ποῦ ποθ' οἱ Φωκῆς ξένοι
οὕς φασ' Ὀρέστην ἡμὶν ἀγγεῖλαι βίον
λελοιπόθ' ἱππικοῖσιν ἐν ναυαγίοις;

Sophocles Electra 1442-1444 R. C. Jebb 1894
[1442]
Which of you can tell me where those Phocian strangers are,
who are said to have brought report for us that Orestes
passed away amidst the shipwrecked chariots?

The lines above are cited to show Aegisthus' understanding of the current scenario. He assumes that the two foreigners have brought news of Orestes death in a chariot wreck. Electra will take advantage of this misunderstanding. Her comments will leave out certain specific information which will allow Aegisthus to supply that information from his [miss]understanding of the scenario. Leaving out that which is obvious, whatever can be assumed, is a normal practice in human dialogue. In the following lines Electra's statements are ambiguous. She omits certain details to keep Aegisthus in the dark about his immanent fate but her wording is also aimed at the audience which knows the whole story. 
 
S.El. 1450-1457
{ΑΙ.} Ποῦ δῆτ' ἂν εἶεν οἱ ξένοι; δίδασκέ με.
{ΗΛ.} Ἔνδον· φίλης γὰρ προξένου κατήνυσαν.
{ΑΙ.} Ἦ καὶ θανόντ' ἤγγειλαν ὡς ἐτητύμως;
{ΗΛ.} Οὔκ, ἀλλὰ κἀπέδειξαν, οὐ λόγῳ μόνον.
{ΑΙ.} Πάρεστ' ἄρ' ἡμῖν ὥστε κἀμφανῆ μαθεῖν;
{ΗΛ.} Πάρεστι δῆτα καὶ μάλ' ἄζηλος θέα.
{ΑΙ.} Ἦ πολλὰ χαίρειν μ' εἶπας οὐκ εἰωθότως.
{ΗΛ.} Χαίροις ἄν, εἴ σοι χαρτὰ τυγχάνει τάδε.

Aegisthus [1450] 
Where, then, are the strangers? Tell me.
Electra [1451]
Inside. They have κατήνυσαν our beloved hostess/patron.
Aegisthus [1452] 
Did they actually report that he truly died?
Electra [1453]
No. Not in words only. They brought evidence. 
Aegisthus [1454]
Is it possible to show me the evidence?
Electra [1455]
It is certainly possible, but it's not a pretty sight.
Aegisthus [1456]
You've given me reason to rejoice, not typical of you.
Electra [1457]
What ever turns you on. 

Line 1451 is somewhat tricky. The referent φίλης ... προξένου "beloved hostess/patroness[1]" is Clytaemnestra. She is a hostess to the two foreigners and a patroness [very sarcastic] to Electra and possibly even Aegisthus. There is no possessive pronoun so the question who's patroness/hostess is left open. The best solution might be to have the hostess/patroness belong to Electra and Aegisthus but the direction of her hospitality at this moment directed at the the two foreigners. All this intended for Aegisthus' picture of the scenario.

The second difficulty at 1451 is the meaning of the verb κατήνυσαν [2] which includes: transitive accomplish, perpetrate and intransitive arrive at a place. Sophocles appears to intend both meanings, one for Aegisthus arrive ... which fits into his understanding of the scenario and another perpetrate for Electra and the audience who know that the two foreigners have just murdered Clytaemnestra.

At first glance Electra's response in line 1453 appears to be a reference to the urn of ashes, ostensibly Orestes remains. But that reading doesn't makes sense with Electra's following comments. There isn't anything gruesome about an urn of ashes. Electra is ad-libbing, fabricating a story about Orestes physical remains, she leaves the nature of the evidence vague but implies that it is more substantial than an urn ashes. Aegisthus supplies the missing information based on his [miss]understanding of the scenario.      

[1] LSJ: ... patron, protector, A.Supp.420 (lyr.), al., Ar.Th.602; φίλης γὰρ π. κατήνυσαν at the house of a kind patroness, i.e. Clytaemnestra, S.El.1451;

[2] LSJ κατ-ᾰνύω, Att. καθ- (q.v.) (κατ-ύτω [ῠ] X.Cyr.8.6.17):—Pass. (v. infr. 11):— bring to an end; esp.

accomplish, cover a certain distance, τὸν προκείμενον δρόμον Hdt.8.98; νηῦς -ανύει ἐν μακρημερίῃ ὀργυιὰς ἑπτακισμυρίας Id.4.86; δυοῖν ἡμέραιν ὁδὸν ἐν μιᾷ X.HG5.4.49, etc.; then,

intr., arrive at a place, νηῒ κατανύσας ἐς Αῆμνον Hdt.6.140, cf. X.HG5.4.20: c. gen., φίλης γὰρ προξένου (sc. ἐς οἶκον） κατήνυσαν they have come to a kind hostess's, S.El.1451: metaph., πρὶν σᾶν . . κατανύσαι φρενῶν before thou arrivest at thy purpose, E. Hipp.365 (s. v.l., lyr.).

accomplish, perpetrate, τάδε Id.El.1163 (lyr.); αἷμα γενέθλιον κ. Id.Or.89:—Med., πολλὰ τῇ πατρίδι κ. IPE 12.40.10 (Olbia, ii/iii A.D.):—Pass., to be fulfilled, τὸ τέρας αὐτῷ εἰς τὴν ὑπατικὴν ἀρχὴν κατηνύσθη Dam.Isid.64.