"My character is a lost soul," he said.
"Margaret probably has the biggest part, but I have to set the mood of suffering, and portray disability and non-awareness.
"There's a lot of emotions to bring within 45 minutes -- but it must have worked well."
Mr Palmer first appeared on stage was in 1978, alongside daughter Kerryn, in a Greytown Little Theatre production of The Wizard of Oz.
"I had to go with Kerryn to her audition -- she came back with the part of the bluebird, and I with the soldier with the green whiskers.
"I'd never been on a stage before in my life."
Mr Palmer later joined up with almost all Wairarapa's theatre clubs, graduating to roles such as Fagin in Oliver!, Alfie Doolittle in My Fair Lady, Long John Silver in Treasure Island and the title role in Scrooge.
He took a break for eight years, but was coaxed back last year to appear in A Life Sentence for Greytown Little Theatre's one-act play event.
To prepare for his role in Life Sentence, the tale of a woman losing her husband to Alzheimer's, Mr Palmer did a lot of research -- reading "everything [he] could" about the degenerative disease, and talking to those who cared for a spouse or parent.
"I wouldn't wish Alzheimer's on anyone.
"It's so debilitating: my character has forgotten his wife, and doesn't know he's in hospital, or that he's about to die.
"It was completely different to what I was used to -- I couldn't just be Colin for this one."
Before each performance, he would sit alone for at least an hour, thinking solidly about the the distress of watching a loved one succumb.
"After the shows, people would come up to me saying they cried, or that their late husband was just like that."
Mr Palmer looks forward to reprising his role for the regional finals -- though is starting to "get butterflies".
"Who knows what will happen? It could be completely different this round.
"All the same, I've thoroughly enjoyed myself."
