Richardson was rushed to hospital hours after falling and banging her head during a skiing lesson in Canada in 2009 and almost two years later Neeson can still vividly remember the awful night he tried to get access to his dying wife, recalling how security at the hospital was high and no one seemed to know who he was.
He tells Esquire magazine, "I walked into the emergency (room) - it's like 70, 80 people, broken arms, black eyes, all that - and for the first time in years, nobody recognises me. Not the nurses. The patients. No one.
"I've come all this way, and they won't let me see her. And I'm looking past them, starting to push - I'm like, 'F**k, I know my wife's back there someplace.'
"I pull out a cell phone, and a security guard comes up, starts saying, 'Sorry, sir, you can't use that in here,' and I'm about to ask him if he knew me, when he disappears to answer a phone call or something. So I went outside. It's freezing cold, and I thought, 'What am I gonna do? How am I going to get past the security?'
"I see two nurses... I walk up, and luckily one of them recognises me. And I'll tell you, I was so f**king grateful - for the first time in I don't know how long - to be recognised. And this one (nurse) says, 'Go in that back door there.' She points me to it. 'Make a left. She's in a room there.' So I get there, just in time.
"And all these young doctors, who look all of 18 years of age, they tell me the worst."
Richardson, 45, died of an epidural haematoma and Neeson admits he's often overcome with grief at the most random moments when he thinks about his late wife.
He adds, "It hits you in the middle of the night - well, it hits me in the middle of the night. I'm out walking. I'm feeling quite content. And it's like suddenly, boom."