I am currently rereading Harry Potter and the Chamber of Secrets and I was wondering if looking at a basilisk in a memory would cause death? If, eg., Harry had seen the basilisk in Tom Riddle memory, would he have died?
I'm going to say "no", for the simple reason that anyone who stared directly into a basilisk's eyes would be killed, and therefore could not have their memories extracted. If someone looked at a basilisk in a mirror and so were just petrified, their extracted memories might petrify someone else, but not kill them.
This one is hard to answer with canon info, as there isn't any as far as I know
I would guess at a no, but there is a possibility of some damage being done
Reasons for No:
The stare of the basilisk is what is fatal, you need to be looking into it's eyes while it looks back. In the 2nd book after Fawkes poked it's eyes out, it lost it's deadly stare and Harry could look at it directly. As the memory basilisk is not really there, it would have no effect on the onlooker
Reasons for possible damage:
Again from the 2nd book, the basilisk's stare is strong enough to even "kill" off a ghost, and Justin who saw it through Nick got petrified. Even Hermione and Penelope who saw only the reflection of the Basilisk got petrified, though they did not really stare at each other. Hence by this logic, since the memory is of a real basilisk, and when using the pensieve the user seems to be actually physically going into the memory, it can be argued that looking into the eyes of the memory basilisk might do some damage
“I’m sorry,” he said shakily. “I didn’t mean to butt in —”
But the wizard didn’t look up. He continued to read, frowning slightly. Harry drew nearer to his desk and stammered, “Er — I’ll just go, shall I?”
Harry looked around the office. No Fawkes the phoenix — no whirring silver contraptions. This was Hogwarts as Riddle had known it, meaning that this unknown wizard was Headmaster, not Dumbledore, and he, Harry, was little more than a phantom, completely invisible to the people of fifty years ago.
Harry Potter and the Chamber of Secrets, Chapter 13, The Very Secret Diary
This clearly implies that the onlooker does not physically exist in the memory.
Its methods of killing are most wondrous, for aside from its deadly and venomous fangs, the Basilisk has a murderous stare, and all who are fixed with the beam of its eye shall suffer instant death.
Harry Potter and the Chamber of Secrets, Chapter 16, The Chamber of Secrets
From the above we know that a possible victim would have to look into Basilisk's directly to die or indirectly to be petrified.
It is not possible to make actual eye contact in an memory because the onlooker has no physically existence in the memory. So seeing Basilisk in an memory should not cause any harm to the onlooker.
If it's even possible to meet a basilisk's gaze in a memory, and if it's even possible to suffer harm while experiencing a memory, then I'd wager meeting the gaze of a basilisk through a memory would be the same as meeting it indirectly by any other means (a mirror, a camera sight prism, etc.), which means you'd only be petrified.