A question about a recipe: Lobster Diavolo

I have a question about step 4 on the recipe "Lobster Diavolo" from merrill. It says:

"Bring an inch of water to a boil in a large stockpot. Add the lobsters to the pot and cover. Cook for 15 to 20 minutes, until the lobster’s antennae can be easily pulled off. Remove the lobsters from the pot and set aside for a few minutes to cool a little"