Shalit's release **NOW** would undercut a message that Bibi is **NOW** desperately trying to sell overseas. That is the political dynamic that is at work here i.e. Bibi doesn't want anything to undercut his message, but if Shalit looks like being released then Bibi will end up undercut by an event that He Can Not Be Seen To Be Sabotaging.
UN chief condemns Palestinian toddler killing, urges calm (Reuters)
from the article: Egypt pushing Hamas to soften stance on Shalit deal