Inside a nested loop query plan, does sql server wait for one instance of the loop to complete before starting the next one?

I have some queries which are slow and their pattern is index scan->nestedLoop lookup, and i'm reasonably sure that the cache is cold.

Assuming I've a query plan that shows a nested loop with 10000 lookups, If i consistently have a 5ms disk access time, is there any way to work out how long it will take to read the rows (assume 5k page fetches are needed; some of the rows will be on already fetched pages, producting logical but not physical reads).

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