Trying to get a field from a fetched entity in rules
Correct way to get the value is:

&lt;?php print_r($entity_fetched-&gt;field_date_time['und']['0']['value']); ?&gt;


The $entity_fetched is returning an object so to access it values you would need to use -&gt; operator, and than you have array contents which you can access using the array subscript operator []. 

Note: You cannot access object members via the array subscript operator [].
For accessing the object members you need to use the -&gt; operator.
And to access the array contents we use the [] operator.