During the conclave fight, why didn't Heimdall's high priest kill himself?

A god must have a physical representative in the chamber for their vote to count. Nobody may interfere with another god's representative or their guards. No high priest there will go against their god's will.

But Heimdall's high priest knew that his god would change his vote if he could. Hel said as much when she mocked him for not being able to. He wouldn't have interfered with another god's representative. He could have instantly ended the threat. Is there a reason he couldn't? (Keeping in mind that he knows he'll get a good afterlife and that he'll save the world by doing it) Has anyone else already noticed this?

edit: 'kill himself' isn't the same thing as suicide in this context, unless you'd say a soldier committed suicide by jumping on a grenade that landed in the middle of his squadron, or a teacher did by rushing a school shooter. There's a clear, imminent, outside threat to the group; this person is an authority figure charged with protecting the group.