>>100403147If she got it then it would be easier for Thanos to take it away.
She was hoping that it was hidden so well he wouldn't find it but wasn't counting on him making her tell him the location.
Also Thanos wasn't waiting on his ass.
He was waiting for a series of events to transpire and have the ideal conditions to get the stones as quickly as possible before anyone could make plans to stop him.
Odin died and that made the tessaract easy to get.
Since the reality stone couldn't be kept close to the tessaract it was taken out of Asgard and given to the collector which would be easier than getting it from Odin.
The ancient one died on earth making the time stone easy to get.
He had the mind stone but that bumbling idiot Loki lost it but it was on earth with the time stone so that made things easier.
The power stone was easy to find now that it was on xandar.
He wasn't sure where the soul stone was so that was the only one that would be difficult to get.
Thanos has been playing 4d chess for a long time now, just waiting for the right moment to strike quick after a few half-assed attempts to get his minions to get the stones.
He hit everybody quick, caught Thor when he was most vulnerable, and collected the stones as quickly as possible before anyone had time to regroup or prepare for him.