Correct. Only one team is allowed on the ice at a time.

[ His smile actually brightens a bit. He does so love to see a Gold Novice prove they're smart. ]

The rock must be thrown at such a speed that it will reach the target, but slowed by the remaining team members, who use brooms to shift the ice and slow the rock down.

[ It's so simple but it's complex... the beauty of curling. ]

Likewise, teams are not allowed to interfere with another team's thralls. Any instances of foul play are dealt with swiftly and without prejudice.