Dozens of interviews with people deeply familiar or involved with the election process point to a clear consensus: Not only could Trump make a second attempt at overturning an election he loses, he and his allies are already laying the groundwork.
Archived at https://ghostarchive.org/archive/8e3Ri
Also because security mostly refused to use deadly force. Those security forces are mostly used to dealing with tourist issues, not criminals with guns. That may change if more hardened, militarized police forces are used.