I've just lost connection (no actual loss of connection occurred just with the game) twice in a row under the same circumstances. Both times I had just beaten the two body guards, was down to one unit (Slub gut) and slub gut was required to discard. Edit: Also I think the last bodyguard died of burning damage as well in both cases.
Do you mean the game stopped responding? If you lose connection, you'll get a message box on screen. Can you please take a screenshot and report the battle room number? http://forums.cardhunter.com/threads/please-read-how-to-report-bugs.331/
