Usually escape doors should open in the direction of exit. In your case, this might be because the door leads directly onto a fire escape path, in which case it might block the path for people trying to escape if it opened out, or it may block a public right of way. In this instance, outward opening doors are compliant with Building Regs.
The important thing is that they must be unobstructed and easily open-able without the use of a key. It should not be necessary to manipulate more than one mechanism to release the door, ie it should be "simple action".