Upvote:1
The journey from Finsbury Park (FPK) to University College Hospital is so short that the main factors influencing time are likely to be how close you are to the stairs at FPK when you get off the train, how fast you can walk down the stairs, whether you walk down the escalator at King's Cross (KGX) so I think any of the usual on-line sources is going to be heavily influenced by assumptions they make. (You also have the option if you go to KGX of getting the tube to Euston Square which is likely to take about the same time.) So my conclusion is, it is unlikely to make much difference.
Coming back I would suggest routing via KGX as if you try to get on the train at FPK you are less likely to get a seat especially in the rush hour.