The hidden document
Frank enters the vents to retrieve his will while Mac guides him by radio. Charlie’s map and wall markings complicate the search.
Supporting source ↗CASE FILE · S03 E04

The McPoyles invade Paddy's and take the gang hostage, demanding $100,000, a gassed-up boat and a reversible Planet Hollywood jacket. Meanwhile, Frank is crawling through the ductwork above Paddy's, searching for his will, when Liam McPoyle turns up the heat.
THE SHORT VERSION · SPOILERS AHEAD
Frank enters the vents to retrieve his will while Mac guides him by radio. Charlie’s map and wall markings complicate the search.
Supporting source ↗The McPoyles seize Paddy’s. The gang forms and breaks alliances, arguing over who should survive while the captors turn up the heat.
Supporting source ↗Bathrobes, milk and improvised digging give way to a destruction challenge. Mac smashes the bar while Charlie escapes to confront Frank.
Supporting source ↗On the roof, the apparent crisis unravels: the McPoyles have rubber weapons and no police are waiting below. They leave the gang with the damage.
Supporting source ↗THE EVIDENCE
Charlie displays the hidden envelope to Frank above the bar.Source ↗
Dee holds the McPoyles’ prop shotgun between the two brothers.Source ↗
Dennis approaches Margaret in the bar’s bathroom.Source ↗
Frank uses a walkie-talkie and lighter while crawling through the vents.Source ↗
Liam stands to Dee’s left in a striped bathrobe.Source ↗
Margaret remains with Dennis in the bathroom.Source ↗
Ryan wears an open black bathrobe.Source ↗
The three McPoyles confront the gang on the roof.Source ↗
Broken glass and scattered objects cover the bar after the destruction challenge.Source ↗
Charlie shows Frank the envelope he has been seeking.Source ↗
Frank points his real handgun at Charlie in the crawlspace.Source ↗
The gang discovers that the captors’ weapons are rubber props.Source ↗
Frank communicates with Mac using a handheld radio.Source ↗
Charlie’s warning on the vent wall leaves Frank confused.Source ↗
Tags document researched occurrences, not every appearance. Read the research notes and attribution.