In the episode Revenge, Sylvester is seriously injured by an IED which explodes during a case, and this makes the team on edge and unfocused.
Also, at the same time, Drew returns again and asks Paige out on a date, and SImone, an interpol agent is making advances on Walter. Walter, however feels very uncomfortable and doesn't seem to like Simone at all.
Both Walter and Paige would rather be with their new found family within Scorpion and break off their "dates" to be with Sylvester in the hospital. In the end, Paige and Walter sit next to each other and smile at eachother. I feel this small and insignficant act is complete foreshadowing. They are very close friends, and that's where romance begins to root. It also shows how comfortable they are with eachother, and that they have already accepted eachother as family. Walter also comforts Paige and worries about her alot. He admires her as seen him admiring her voice when she was singing, and then staring at her when she was in her dress, and when she had fake snow in her hair.
I believe that Walter and Paige will get together in the future.......
But, we may have to wait a long time like we had to for the Mentalist. In the meantime, continue to ship them Waige shippers! The subtle hints are the ones that promise a future!