"I'd going to ask the lads, and we as coaches and players need to find out what went wrong in that first quarter," he said.
"You can accept that (performance) in the first two years, 18 year-olds playing up against men, in most cases for the first time, but not after three years.
"Not like that. Not when there was so much on the game as well. That's not us."
McKenna described the first quarter as insipid and said it was pointless looking for positives in the final three quarters.
Gold Coast's vaunted young midfield group of Dion Prestia, David Swallow, Jaeger O'Meara and Jack Martin were out-pointed hopelessly by their Lions counterparts.
They were thumped in the clearances 55-34. Tom Rockliff (11), Dayne Zorko (10) and Pearce Hanley (nine) had almost as many clearances as the entire Suns team.
"We looked slow, we looked lost at stoppages, but that hasn't been the case for most of the year," McKenna said.
"Why did it happen tonight? Seriously I can't answer that."
He said with five games remaining, Gold Coast had not lost hope of qualifying for its first finals appearance.
However, he refused to blame the season-ending injury to skipper Gary Ablett for the lacklustre losses against the Western Bulldogs and Lions.
"We won a quarter against Collingwood (without Ablett), quarter and 10 minutes, with no rotations and backs to the wall … it's a quarter we won.
"Bulldogs touched us up in the contested footy and I'm talking big numbers. And then 36 to 126 possessions (in the first quarter against the Lions), we were beaten inside and outside again. That's not us."