Set the Instant Pot in the saute mode, adjust the temperature to less. When the Instant Pot reads hot, add butter and allow it to melt. Add shrimp along with garlic and saute it for a minute or two [ see note].
Add TABASCO® sauce and macaroni pasta along with water, and salt. Cancel the saute mode and switch to the 'Pressure Cook' or 'Manual' mode. Set it for low pressure and adjust the time to 4 minutes.
Once the cooking cycle is complete, do a quick release i.e move the vent towards venting to release steam. Set the Instant Pot to saute mode again and adjust the temperature to 'Less'. Add milk, along with the cheese and pepper and mix well.
Continue to cook until all the liquid has absorbed and the mac and cheese is in a consistency that you like.
You can always saute the shrimp and garlic over the stove top and serve it as a side with mac and cheese. That way you don’t have to cook a different version for the kids or for anyone who prefers the classic recipe.