I have the 6910 which has the first shower screen and a second dispersing screen behind which usually just comes out with the first one. After this is removed the seal should be able to be removed without unscrewing anything else.
It probably has just got some coffee residue acting as a glue and sticking it up in the head. I sometimes just use a small scewdriver to loosen the edges and out it comes.
If your going to replace it I wouldnt worry about being too careful with it.