Unfortunately I have no other advice to give apart from reading over the walkthrough and/or trying to reload a saved game before entering the lab and playing through it again.
I had someone here about a month ago asking for a saved game for this part - I sent her a saved game, but apparently the save only takes you through the seeds puzzle but does not get you out of the lab, so that would not help in this situation.
There is a video walkthrough of the game on YouTube that starts here
and you could watch that - maybe something there would help. I am not sure which part of the walkthrough you would need, but you could check it out.
I wish I had something else to suggest. Maybe another player will see this thread and offer some additional advice.