Initially, when the British military learned that the Chimera were advancing onto London, the base and all 94,000 troops inside it were sealed to prevent Crawlers from entering and infecting the entire base. However, with many troops and personnel inside it only meant that the Chimera would tried to break in through very high tactical means. Eventually many soldiers were killed, and some left the base to try and get to other command posts or just try in vain to destroy all the Chimera outside. By October 1950 only about 14,200 soldiers remained in the base and the Chimera penetrated the base from below using Burrowers loaded with Slipskulls. British personnel repelled the first assault. A week later on October 14th, the Chimera burrow in again, this time from the River Thames, thereby flooding the base, as it had been sealed and the water couldn't get out, killing 14,000 soldiers. Of the 200 soldiers who survived, many were then lured into the water by Sirens and were killed. Some, however, managed to escape into London.