Last Ice Horse

The chains created by the defender from squad one could only last for a short amount of time. After ten seconds the chains would dissappear and it would take ten seconds before the chains could be used again.

Even if only one set of chains is being used, the wait time stays the same. The chains all disappear at the same time regardless of when they were summoned in the ten second period of use.

Because of this, the ice horses that were being kept back earlier in the fight were technically still able to participate for ten seconds at a time.

The ice horse wasn't a particularly fast or flexible creature, so after being trapped by the chains it would take almost the entire ten seconds for them to get up from the ground and start moving towards the fight. 

The wind wolves were a completely different story in this regard, they seemed to specialize in speed and were capable of getting up within a second after the chains disappeared.