There have been dramatic scenes in Cairo's Tahrir Square as pro-Hosni Mubarak supporters clashed with opposition demonstrators. In the ensuing carnage, several people were killed and hundreds were injured. The country's military is increasingly being criticised for standing on the sidelines and watching the bloodshed unfold. So what is the army's role in this crisis and for how long can they stand aside and watch Egypt descend into chaos? Inside Story discusses.