The waiter acts first
Frank’s friends watch him choke. The waiter rescues him, prompting an intrusive attempt at friendship.
Supporting source ↗CASE FILE · S14 E04

Annoyed that the Gang failed to react as he nearly choked to death on an appetizer, Frank decides the Waiter, his savior, is the only person who has his back.
THE SHORT VERSION · SPOILERS AHEAD
Frank’s friends watch him choke. The waiter rescues him, prompting an intrusive attempt at friendship.
Supporting source ↗Mac secretly feeds Dennis ingredients he avoids, hoping illness will make Dennis dependent on him.
Supporting source ↗Frank disrupts the waiter’s home, relocates his mother and leaves him with unaffordable commitments.
Supporting source ↗A planned rescue of Frank collapses when Dee consumes the poisoned shake. The waiter intervenes again.
Supporting source ↗THE EVIDENCE
Charlie holds a basketball on the outdoor court.Source ↗
Dee lies on the restaurant floor as the waiter intervenes.Source ↗
Dennis questions Mac at their breakfast table.Source ↗
Frank sits at the waiter’s table with a hammer nearby.Source ↗
The waiter confronts Frank in his home.Source ↗
The waiter’s mother sits at the table beside Frank.Source ↗
Charlie speaks to Frank in their apartment.Source ↗
Mac and Charlie discuss the shakes in the apartment.Source ↗
The gang returns to this dining room after recognizing the waiter.Source ↗
The waiter reveals his mother beneath the covering in their living room.Source ↗
Frank wears thick dark-framed glasses at the restaurant.Source ↗
A television faces the couch where Dennis is lying down.Source ↗
Charlie holds one of Mac’s blended drinks.Source ↗
Dee drinks the shake intended for Frank.Source ↗
Mac intends to rescue Frank after poisoning him.Source ↗
Frank wears his dark wig to dinner.Source ↗
Charlie holds the ball while Mac and Dennis remain by the fence.Source ↗
Tags document researched occurrences, not every appearance. Read the research notes and attribution.