Some conflicts are worth dying for if you are protecting those you love from a determined foe. Yet most of the people are driven away by the thought of death, so retreat becomes the only option. And that's exactly what Arnold was making the soldiers do.
While Arnold was explaining the situation to his trusted companions, someone overheard him. The news of a possible nuclear explosion spread like a wildfire. Everyone grew restless and even though the portal Arnold had generated was gigantic, there was a rush to escape.
The swamp was thrown into an uproar. Some soldiers were carefully falling back into the travel portal while Arnold's summons protected them from the onslaught of the lizardmen. While the rest had abandoned all sense of reason and were getting more and more restless by the moment.