Maurice Couturier: "There may be yet another interpretation of line 992: Kinbote, in his commentary to the previous line, says that Shade was "hampered in his movements" as he descended the steps of the porch, and he "relieved" him of his manuscript to help him. After the shooting, he acts as if he were a drunk. Yet,it would mean that Shade, when writing this line, was foreshadowing his forthcoming situation, a little far-fetched, I grant it. We probably miss something. I am tempted to make allowance for this possible interpretation in my revision of the translation for the Pléiade edition."

Jansy Mello: Shade acts as if he were a drunk, or was he, in fact, addicted to alcohol, hiding his drinking habits from Sybil (but she must have smelled his breath, like Kinbote did)and and easy to lure away from his perch by a promise of, perhaps, another a glass of Tokay? Besides, he was not very steady on his feet independently of that. I see no reason to suppose he was "foreshadowing his forthcoming situation" (foreshadowing is a very apt term, it adds a particular tonality to PF's first lines about the waxwing's shadow)

"From the inside of the supermarket, through a plate-glass window, I saw the old chap pop into a liquor store.[ ] A comfortable burp told me he had a flask of brandy concealed about his warmly coated person.." Foreword

"My binoculars would seek him out and focus upon him [ ] lurking in the ruptured shadows of his first-floor study where a bright goblet of liquor quietly traveled from filing cabinet to lectern, and from lectern to bookshelf, there to hide if need be behind Dante’s bust; on a hot day..." Note to lines 47-48
"I started to calculate aloud in meters the altitude that I thought much too high for John’s heart but Sybil pulled him by the sleeve reminding him they had more shopping to do, and I was left with about 2,000 meters and a valerian-flavored burp." Note to line 287

René Alladaye: "There seem to be at least two possible ways of reading line 992. The first one has to do with the horseshoes mentioned in the previous line. The horseshoe game is played by pitching horseshoes as close as possible to a stake which is also called a “leaner”. If the horseshoe is pitched so close that it leans against the stake, the image in the poem is easier to understand.[ ]But there still remains a slight grammatical problem (ignored by the French translators) as “horseshoes” in line 991 is plural and does not agree with “its”. This leads me to my second hypothesis. What if line 992 refers to line 990 and it is Sybil’s shadow which does the leaning against the shagbark tree. The tree is now compared to a lamppost and the shadow looks like a drunk because it is aslant. [ ]The line order adopted in the poem leads me to conclude that Shade (or/and Nabokov of course) wants to preserve the dual reading and force his reader to hesitate. This would not be particularly surprising in Pale Fire where enigmatic passages are numerous."

Jansy Mello: The idea about a "dual reading" of the line is particularly appealing to me. However, there's Barrie Akin's observation to consider: "The alternative of Sybil's shadow did occur to me, but the part that hits the tree would look as straight as the tree, so I discounted it." Would Sybil's shadow appear straight or aslant? Is it a matter of perspective informing about Sybil's closeness to the scene? .