Conversation so far:
What did the Kray twins have to do with the National Service in the British Army?
The Krays were called up to do National Service in the British Army in March 1952
What did the Kray twins do at the depot of the Royal Fusillers?
Although the Kray twins reported to the depot of the Royal Fusiliers at the Tower of London, they attempted to leave after only a few minutes.

Question: why did they attempt to leave?
Self-contained rewrite: Why did the Kray twins attempt to leave the depot of the Royal Fusillers?