Staying in would mean we will continue with free movement of people.
within the EU for people with EU citizenship status.

The worry is that there could be a modern day Trojan Horse type plot
with large groups of ISIS fighters entering Europe amongst genuine asylum seekers.
This worry could be partly due to the number of men arriving (72% men, 13% women, 15% children).

The recent Attack on Paris was carried out by terrorists based in Belgium with free cross border movement with France, this coupled with the evidence that some of the terrorists
had been using the migrant routes to travel between the middle east and Europe
highlights this danger.