The motion was sponsored by the NDP. Shea had been in the House all evening, but got up and left just before the vote.
Liberal MP for Charlottetown Sean Casey was in the House at the time and he said he couldn't believe his eyes.
"Shocked. Absolutely shocked. I have never ever seen anyone leave in the middle of a vote," said Casey.
"Now, I've only been there a year and a half. But my colleagues who have been there much longer, they were absolutely dumbfounded to see a minister of the Crown, a regional minister, on an issue that is of critical importance to the region where she is the regional minister."
Casey said there is no doubt in his mind Shea was trying to avoid having her vote recorded on the motion.
When asked if it was plausible Shea might have had somewhere to be, Casey said her turn to vote was in a matter of minutes. If Shea had somewhere to go, he said she would have been no more than three minutes late if she'd stayed to vote.
In a phone call to CBC News, Shea's office said the minister had to leave the House for personal reasons.Suggest a correction