Maloof makes a detailed examination of the chest. Are there any unusual marks or holes on the floor, walls, or ceiling around the chest? Or on the chest itself? How does the chest open? Does it have a latch or a lock? Is it made of wood, with metal lock/hinges? Are the hinges exposed? Are there carry-handles on the outside of the chest? Is the chest sitting flush against the wall, or out in the open? By "fairly sizeable" I'm thinking roughly 1m x 0.5m x 0.5m?
If anything looks suspicious, Maloof will cast Find Traps.
If everything looks fine, Maloof will first attempt to move the chest across the floor to see if anything happens (he will avoid standing in front of the chest, and will avoid using any carry-handles if present. Rather, he will lie on the floor and use his feet to push the chest. If this goes off smoothly (whether or not he is successful, the chest may be too heavy), he will attempt to open the chest by crouching to the side and using his mace to lift the lid. If there is some sort of latching mechanism which would require greater manual dexterity, he will attempt to use his wooden cross as a proxy to manipulate the lock/latch, again carefully crouching or lying as low and as far to the side as he is able while doing so.