But Rice could not care less as his basement boys recorded their first win in 10 games to breath fresh life into their relegation rescue mission.
Aberdeen target Jamie McGrath's 16th goal of the season made the final moments tense.
However, Hamilton held on for a win which means they are separated from drop-zone rivals Kilmarnock and Ross County by just three points, with Accies heading to Dingwall a week on Wednesday before hosting Killie on the final day.
Buddies boss Jim Goodwin was hoping to give key men McGrath and Conor McCarthy the afternoon off ahead of next week's Scottish Cup semi-final with St Johnstone.
But an injury to Marcus Fraser in the warm-up meant defender McCarthy was forced into action from the start.
Rice was confined to a seat in the stand following his angry outburst after the clubs' cup meeting earlier this month.
But with the Accies boss perched just seven rows back in the Main Stand, the visitors had no trouble making out his shouts.
But Rice was out of his seat celebrating after 28 minutes as Callachan converted his next chance.
St Mirren failed to clear Aaron Martin's deep free-kick and found themselves pinned down.
Pint-sized Accies midfielder Reegan Mimnaugh jumped higher than Ethan Erhahon to knock the ball out to Lee Hodson, whose lofted delivery back into the middle was turned home by Callachan's scuffed finish.
Yet the goalscorer was lucky to see the half-time whistle.
Callachan – already on a booking for almost putting Saints youngster Jay Henderson into the stand with a forceful shoulder barge – escaped a second after 38 minutes after launching into a clumsy tackle from behind on Erhahon.
Rice's ban meant he was also locked out of the dressing room at half-time so he spent the interval anxiously pacing the stand.
But his worries were eased after 57 minutes as his side got a major break of the ball for the second.
On-loan Aberdeen ace Bruce Anderson's strike was going well wide before it smacked Moyo's shins and trickled over the line.
Callachan then shook the bar with a shuddering strike while Rice allowed himself a smile as Moyo got an attempted overhead kick all wrong.
But the Hamilton manager's frown returned with 19 minutes left as Saints did pull one back.
Goodwin made a triple change and it paid off as two were involved in the goal as substitute McGrath swept home with a tidy finish after fellow replacement Ilkay Durmus' cross had spilled off Henderson's shins.
Rice then had to hold his breath with seven minutes left when a mistake by Gourlay saw Henderson burst through on goal but the Saints youngster blazed his shot to Accies' huge relief.