When Owen and Maggie are sitting on the ledge and she flips her cigarette, you can see a line coming out from behind Owen. The line can also be seen in the opening scene when he first says "So, are you ready to jump?" Presumably, a safety line was attached to his harness to keep him from falling off.
When Tosh comes to Owen's home and is saying she wants to help him (28:50), you can see the reflection of a man passing by in a mirror behind Owen.
When Tosh comes to Owen's home and is saying she wants to help him (18:50) you can see the reflection of a man passing by in a mirror behind Owen.