On Chicago Fire's most recent episode, Casey (Jesse Spencer) was forced to make a gut-wrenching decision about who to save from a burning building: A man who pointed a gun at him while begging for his life, or a woman and a young child. Casey chose the latter, but when he went back in to try to get to the first victim, the man was nowhere to be found.

In an exclusive clip from next week's episode, the man is back — and holding a dangerous grudge against Casey and, by extension, Dawson (Monica Raymund). He tracks them down in a grocery store while they're out doing their weekly shopping and shows Dawson a nasty-looking burn on his forearm before hissing a thinly-veiled threat at her.

We already know the man has a gun, and now he's got a vendetta against Casey and the rest of 51 to go with it. Check out the clip to see his full encounter with Dawson, as well as how she and Casey react.

Chicago Fire airs Tuesdays at 10/9c on NBC.