From the point of view of strict practicality, if Calder had stuck to a one- or two-word term ("slave", "minion") he might have been able to get out a command in the second panel.
Do we know for sure that he was aware for decades? Page 1295 implied that he didn't know how long he'd been stuck there. Though it would be challenging to keep track of time, under the circumstances, if he'd been conscious-but-contained for that long.
"It isn't etiquette to cut any one you've been introduced to." -- Through the Looking-Glass, Lewis Carroll