Tony doesn’t keep cans of beer or soda in the tower. On the rare occasion that cans are brought into the tower, there is a strict rule among the Avengers that the person opening the can must warn the others before hand (it has typically come down to simply announcing “Can!”).
The reason for this rule can be stated simply: PTSD (Post Traumatic Stress Disorder). To individuals who have been in an army or combat situation, the click of a soda can opening can resemble the sound of a gun being loaded.
The Avengers all have different responses to this. Steve tends to simply jump or flinch, but isn’t too bothered by it at this point. Tony shows no physical response, but it has been noted that he tends to down his drink faster than normal afterwards. Clint, if he hears the sound, tends to respond by aiming the nearest projectile in the direction of the sound. If Natasha is close enough to the opener, she will drop them like a stone. Bruce claims the sound doesn’t bother him, but the others have noticed he gets… twitchy.
Shanta has learned to just go for the bottles of soda.
Thor has even developed a response to the sound. It mostly consists of getting out of the others’ way. However, as he often forgets his friends’ responses, and he has taken quite a liking to the sugary, foaming liquid, he is usually one of two culprits for forgetting the warning.
The second culprit is Loki, and though he claims ignorance, the others are certain that, true to his nature, he’s simply stirring up mischief.
