It shouldn't kick you out of ketosis but the calorie and fat content of the oil will be quite high. If you have to do this again I think a better suggestion would be tuna in spring water.
I might be wrong but I think the emphasis on 'staying in ketosis' clouds the view of calorie/fat intake. I know from my days on Atkins I could be in ketosis but easily eating 2000 calories and 200g of fat.
Yes, I stayed in ketosis but that was only part of the bigger picture.