I always assumed that on his way to the lot he ran into Collins and Angel and returned back to the loft with them.
"except isn't he already back in the apt. before collins and angel show up? I mean he doesn't walk in with them if I remember the staging correctly."
I took that as Mark went in first to introduce them to Roger with the line "Enter Tom Collins, computer genious, teacher, vagabond anarchist who ran naked through the Parthanon..." I don't think Makr was actually there before him...does this make sense?
"Because what is more like love than the ocean? You can play in it, drown in it. It can be clear and bright enough to hurt your eyes, or covered in fog; hidden behind a curve of road, and then suddenly there in full glory. Its waves come like breaths, in and out, in and out, body stretched to forever in its possibilities, and yet its heart lies deep, not fully knowable, inconceivably majestic."