My wife is deathly allergic to seafood. If she gets something that has been fried on the same grill or in the same oil as fish or prawns it can cause her all sorts of difficulties up to making her airway swelling shut.
“Cross-contamination” in the kitchen can be just as lethal as eating the offending food.
Best to alert the wait staff immediately.....some restaurants have become very aware of the issues with allergies.