Ryley has access to the Stasis Rifle, Repulsion Cannon and his PRAWN can withstand greater depth pressure. Also he survived the planet despite being infected by the Kharaa so lorewise he was under a time pressure to reach his goals.
In a 1v1 Riley would win be cause of better weaponry and such, but I think Al-an would just flat out destroy Riley if he hurt Robin (especially if it was a fight to the death)
