Separate, But Stable
Their experience in the vault not only initiated the process of unlocking their hearts, but also started them on a path to each other. It's a journey that began to find expression in their seating situation on the Walker's front porch.
As they sit across from the recently reconciled husband and wife, Shane and Oliver are seated together, but separately, in two white chairs. Unlike when they're dancing---which I find incredibly fascinating---Shane and Oliver are facing the same direction as they're seated. It flows well with the idea that both parties in a relationship have to be "going to the same direction" to be successful.
At the same time, Shane and Oliver seem to still be operating out of the same emotional place that characterized their interactions in the vault. There is optimism in that "[Jonathan and Katherine] lived," that they delivered the box, Oliver even encourages the current Walker generation to "read [the letters] out loud---together."
It was an optimism that grew as time passed, and Shane and Oliver got to know each other better, eventually finding expression in more tangible ways.
A Delicate Balance
What's interesting about the swing, much like Shane and Oliver's relationship at this stage, is that it's very tenuous and requires a lot of tinkering. Even the slightest things can upset the balance. Just as Shane and Oliver determined in Truth Be Told, "it takes, two people" to stabilize the swing, or a relationship. It's no surprise, then, that when Hazel mistook Oliver for Steve, it sent the swing, and the budding relationship, into a state of unbalance. For the swing, it was only a temporary state of affairs, rectified when Oliver made superficial adjustments with his buzz saw. Shane and Oliver's relationship, however, was not so easily set straight.
A Solid Foundation
One of their most profound exchanges takes place as Shane and Oliver are seated together on a pew in the hospital chapel in Lost Without You. Here it's Shane that appears in an unexpected venue, much to Oliver's surprise. It seems that the step Oliver made towards Shane in From Paris With Love is reciprocated here as Shane meets him somewhere that is close to his heart. It is the evidence of the finished work that took place at El Dorado Canyon, where each express a new piece of themselves, i.e. the spiritual growth that drew Shane to the chapel, the consequence of which would allow her to achieve more emotional freedom overall, and the new level of emotional freedom which Oliver explicitly describes throughout the scene.
This is the first time since the porch swing that we see Shane and Oliver seated side-by-side in this way, facing the same direction. They meet each other in a new space, on a firm and already established church pew. Neither have to make the pew they share stable. I like to think that, as discussed in The Father's House, their shared prayers for each other brought them into agreement with God, who tied them together in love, becoming their stable foundation as a result, symbolized by the pew on which they sit.
With each step, Shane and Oliver's relationship became established on more and more stable foundations, symbolized by their transition from the separate, but equal, chairs on the Walker porch, to the tenuous porch swing, and ultimately to the divinely established chapel pew on which they sat together, facing the same direction. And it's from this foundation which Shane and Oliver endured their greatest relationship trial to date in Higher Ground.